Differentiation of Urine-Derived Human Induced Pluripotent Stem Cells to Alveolar Type II Epithelial Cells

Exploiting urine-derived induced pluripotent stem cells for advancing precision medicine in cell therapy, disease modeling, and drug testing

The field of regenerative medicine has witnessed remarkable advancements with the emergence of induced pluripotent stem cells (iPSCs) derived from a variety of sources. Among these, urine-derived induced pluripotent stem cells (u-iPSCs) have garnered substantial attention due to their non-invasive and patient-friendly acquisition method. This review manuscript delves into the potential and application of u-iPSCs in advancing precision medicine, particularly in the realms of drug testing, disease modeling, and cell therapy. U-iPSCs are generated through the reprogramming of somatic cells found in urine samples, offering a unique and renewable source of patient-specific pluripotent cells. Their utility in drug testing has revolutionized the pharmaceutical industry by providing personalized platforms for drug screening, toxicity assessment, and efficacy evaluation. The availability of u-iPSCs with diverse genetic backgrounds facilitates the development of tailored therapeutic approaches, minimizing adverse effects and optimizing treatment outcomes. Furthermore, u-iPSCs have demonstrated remarkable efficacy in disease modeling, allowing researchers to recapitulate patient-specific pathologies in vitro. This not only enhances our understanding of disease mechanisms but also serves as a valuable tool for drug discovery and development. In addition, u-iPSC-based disease models offer a platform for studying rare and genetically complex diseases, often underserved by traditional research methods. The versatility of u-iPSCs extends to cell therapy applications, where they hold immense promise for regenerative medicine. Their potential to differentiate into various cell types, including neurons, cardiomyocytes, and hepatocytes, enables the development of patient-specific cell replacement therapies. This personalized approach can revolutionize the treatment of degenerative diseases, organ failure, and tissue damage by minimizing immune rejection and optimizing therapeutic outcomes. However, several challenges and considerations, such as standardization of reprogramming protocols, genomic stability, and scalability, must be addressed to fully exploit u-iPSCs' potential in precision medicine. In conclusion, this review underscores the transformative impact of u-iPSCs on advancing precision medicine and highlights the future prospects and challenges in harnessing this innovative technology for improved healthcare outcomes.

Urine-derived stem cells: Promising advancements and applications in regenerative medicine and beyond

Currently, stem cells are a prominent focus of regenerative engineering research. However, due to the limitations of commonly used stem cell sources, their application in therapy is often restricted to the experimental stage and constrained by ethical considerations. In contrast, urine-derived stem cells (USCs) offer promising advantages for clinical trials and applications. The noninvasive nature of the collection process allows for repeated retrieval within a short period, making it a more feasible option. Moreover, studies have shown that USCs have a protective effect on organs, promoting vascular regeneration, inhibiting oxidative stress, and reducing inflammation in various acute and chronic organ dysfunctions. The application of USCs has also been enhanced by advancements in biomaterials technology, enabling better targeting and controlled release capabilities. This review aims to summarize the current state of research on USCs, providing insights for future applications in basic and clinical settings.

Urine-Derived Stem Cells for Epithelial Tissues Reconstruction and Wound Healing

Epithelial tissue injury can occur on any surface site of the body, particularly in the skin or urethral mucosa tissue, due to trauma, infection, inflammation, and toxic compounds. Both internal and external body epithelial tissue injuries can significantly affect patients’ quality of life, increase healthcare spending, and increase the global economic burden. Transplantation of epithelial tissue grafts is an effective treatment strategy in clinical settings. Autologous bio-engineered epithelia are common clinical skin substitutes that have the specific advantages of avoiding tissue rejection, obviating ethical concerns, reducing the risk of infection, and decreasing scarring compared to donor grafts. However, epithelial cells are often obtained from the individual’s skin and mucosa through invasive methods, which cause further injury or damage. Urine-derived stem cells (USC) of kidney origin, obtained via non-invasive acquisition, possess high stemness properties, self-renewal ability, trophic effects, multipotent differentiation potential, and immunomodulatory ability. These cells show versatile potential for tissue regeneration, with extensive evidence supporting their use in the repair of epidermal and urothelial injuries. We discuss the collection, isolation, culture, characterization, and differentiation of USC. We also discuss the use of USC for cellular therapies as well as the administration of USC-derived paracrine factors for epidermal and urothelial tissue repair. Specifically, we will discuss 3D constructions involving multiple types of USC-loaded hydrogels and USC-seeded scaffolds for use in cosmetic production testing, drug development, and disease modeling. In conclusion, urine-derived stem cells are a readily accessible autologous stem cell source well-suited for developing personalized medical treatments in epithelial tissue regeneration and drug testing.

Urine-Derived Stem Cells for Regenerative Medicine: Basic Biology, Applications, and Challenges

Regenerative medicine based on stem cell research has the potential to provide advanced health care for human beings. Recent studies demonstrate that stem cells in human urine can serve as an excellent source of graft cells for regenerative therapy, mainly due to simple, low-cost, and noninvasive cell isolation. These cells, termed human urine-derived stem cells (USCs), are highly expandable and can differentiate into various cell lineages. They share many biological properties with mesenchymal stem cells, such as potent paracrine effects and immunomodulation ability. The advantage of USCs has motivated researchers to explore their applications in regenerative medicine, including genitourinary regeneration, musculoskeletal repair, skin wound healing, and disease treatment. Although USCs have showed many positive outcomes in preclinical studies, and although the possible applications of USCs for animal therapy have been reported, many issues need to be addressed before clinical translation. This article provides a comprehensive review of USC biology and recent advances in their application for tissue regeneration. Challenges in the clinical translation of USC-based therapy are also discussed. Impact statement Recently, stem cells isolated from urine, referred to as urine-derived stem cells (USCs), have gained much interest in the field of regenerative medicine. Many advantages of human USCs have been found for cell-based therapy: (i) the cell isolation procedure is simple and low cost; (ii) they have remarkable proliferation ability, multidifferentiation potential, and paracrine effects; and (iii) they facilitate tissue regeneration in many animal models. With the hope to facilitate the development of USC-based therapy, we describe the current understanding of USC biology, summarize recent advances in their applications, and discuss future challenges in clinical translation.

Identification of New Transcription Factors that Can Promote Pluripotent Reprogramming

BACKGROUND

Four transcription factors, Oct4, Sox2, Klf4, and c-Myc (the Yamanka factors), can reprogram somatic cells to induced pluripotent stem cells (iPSCs). Many studies have provided a number of alternative combinations to the non-Yamanaka factors. However, it is clear that many additional transcription factors that can generate iPSCs remain to be discovered.

METHODS

The chromatin accessibility and transcriptional level of human embryonic stem cells and human urine cells were compared by Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) and RNA sequencing (RNA-seq) to identify potential reprogramming factors. Selected transcription factors were employed to reprogram urine cells, and the reprogramming efficiency was measured. Urine-derived iPSCs were detected for pluripotency by Immunofluorescence, quantitative polymerase chain reaction, RNA sequencing and teratoma formation test. Finally, we assessed the differentiation potential of the new iPSCs to cardiomyocytes in vitro.

RESULTS

ATAC-seq and RNA-seq datasets predicted TEAD2, TEAD4 and ZIC3 as potential factors involved in urine cell reprogramming. Transfection of TEAD2, TEAD4 and ZIC3 (in the presence of Yamanaka factors) significantly improved the reprogramming efficiency of urine cells. We confirmed that the newly generated iPSCs possessed pluripotency characteristics similar to normal H1 embryonic stem cells. We also confirmed that the new iPSCs could differentiate to functional cardiomyocytes.

CONCLUSIONS

In conclusion, TEAD2, TEAD4 and ZIC3 can increase the efficiency of reprogramming human urine cells into iPSCs, and provides a new stem cell sources for the clinical application and modeling of cardiovascular disease.

Neurons derived from human-induced pluripotent stem cells express mu and kappa opioid receptors

Neuroprotection studies have shown that induced pluripotent stem (iPS) cells have the possibility to transform neuroprotection research. In the present study, iPS cells were generated from human renal epithelial cells and were then differentiated into neurons. Cells in the iPS-cell group were maintained in stem cell medium. In contrast, cells in the iPS-neuron group were first maintained in neural induction medium and expansion medium containing ROCK inhibitors, and then cultivated in neuronal differentiation medium and neuronal maturation medium to induce the neural stem cells to differentiate into neurons. The expression of relevant markers was compared at different stages of differentiation. Immunofluorescence staining revealed that cells in the iPS-neuron group expressed the neural stem cell markers SOX1 and nestin on day 11 of induction, and neuronal markers TUBB3 and NeuN on day 21 of induction. Polymerase chain reaction results demonstrated that, compared with the iPS-cell group, TUBB3 gene expression in the iPS-neuron group was increased 15.6-fold. Further research revealed that, compared with the iPS-cell group, the gene expression and immunoreactivity of mu opioid receptor in the iPS-neuron group were significantly increased (38.3-fold and 5.7-fold, respectively), but those of kappa opioid receptor had only a slight change (1.33-fold and 1.57-fold increases, respectively). Together, these data indicate that human iPS cells can be induced into mu opioid receptor- and kappa opioid receptor-expressing neurons, and that they may be useful to simulate human opioid receptor function in vitro and explore the underlying mechanisms of human conditions.

Urine-derived stem/progenitor cells: A focus on their characterization and potential

Cell therapy, i.e., the use of cells to repair an affected tissue or organ, is at the forefront of regenerative and personalized medicine. Among the multiple cell types that have been used for this purpose [including adult stem cells such as mesenchymal stem cells or pluripotent stem cells], urine-derived stem cells (USCs) have aroused interest in the past years. USCs display classical features of mesenchymal stem cells such as differentiation capacity and immunomodulation. Importantly, they have the main advantage of being isolable from one sample of voided urine with a cheap and unpainful procedure, which is broadly applicable, whereas most adult stem cell types require invasive procedure. Moreover, USCs can be differentiated into renal cell types. This is of high interest for renal cell therapy-based regenerative approaches. This review will firstly describe the isolation and characterization of USCs. We will specifically present USC phenotype, which is not an object of consensus in the literature, as well as detail their differentiation capacity. In the second part of this review, we will present and discuss the main applications of USCs. These include use as a substrate to generate human induced pluripotent stem cells, but we will deeply focus on the use of USCs for cell therapy approaches with a detailed analysis depending on the targeted organ or system. Importantly, we will also focus on the applications that rely on the use of USC-derived products such as microvesicles including exosomes, which is a strategy being increasingly employed. In the last section, we will discuss the remaining barriers and challenges in the field of USC-based regenerative medicine.

Alveolar Type 2 Epithelial Cells as Potential Therapeutics for Acute Lung Injury/Acute Respiratory Distress Syndrome

Acute lung injury/acute respiratory distress syndrome is a common clinical illness with high morbidity and mortality, which is still one of the medical problems urgently needed to be solved. Alveolar type 2 epithelial cells are an important component of lung epithelial cells and as a kind of stem cells, they can proliferate and differentiate into alveolar type 1 epithelial cells, thus contributing to lung epithelial repairment. In addition, they synthesize and secrete all components of the surfactant that regulates alveolar surface tension in the lungs. Moreover, alveolar type 2 epithelial cells play an active role in enhancing alveolar fluid clearance and reducing lung inflammation. In recent years, as more advanced approaches appear in the field of stem and progenitor cells in the lung, many preclinical studies have shown that the cell therapy of alveolar type 2 epithelial cells has great potential effects for acute lung injury/acute respiratory distress syndrome. We reviewed the recent progress on the mechanisms of alveolar type 2 epithelial cells involved in the damaged lung repairment, aiming to explore the possible therapeutic targets in acute lung injury/acute respiratory distress syndrome.

Differentiation of Urine-Derived Induced Pluripotent Stem Cells to Neurons, Astrocytes, and Microvascular Endothelial Cells from a Diabetic Patient

Complications of central nervous system in type 2 diabetes mellitus (T2DM) often lead to cognitive impairment and seriously affect the quality of life. However, there is no individualized disease model. Urine-derived stem cells can be an ideal source for generating human induced pluripotent stem cells (hiPSCs) and progenitors, as they are easily accessible, noninvasive, and universally available. In our research, we differentiated urine-derived hiPSCs into neuron (N), astrocyte (A), and microvascular endothelial cells (E) from a T2DM patient. Next step, we intend to coculture these three cells together in a 3D system to create a new disease model in vitro, which may simulate the cerebral microenvironment of DM, for future study of its pathogenesis and precision medical treatment.

Urine-Derived Stem Cells: Applications in Regenerative and Predictive Medicine

Despite being a biological waste, human urine contains a small population of cells with self-renewal capacity and differentiation potential into several cell types. Being derived from the convoluted tubules of nephron, renal pelvis, ureters, bladder and urethra, urine-derived stem cells (UDSC) have a similar phenotype to mesenchymal stroma cells (MSC) and can be reprogrammed into iPSC (induced pluripotent stem cells). Having simple, safer, low-cost and noninvasive collection procedures, the interest in UDSC has been growing in the last decade. With great potential in regenerative medicine applications, UDSC can also be used as biological models for pharmacology and toxicology tests. This review describes UDSC biological characteristics and differentiation potential and their possible use, including the potential of UDSC-derived iPSC to be used in drug discovery and toxicology, as well as in regenerative medicine. Being a new cellular platform amenable to noninvasive collection for disease stratification and personalized therapy could be a future application for UDSC.

[Construction and preliminary study on biological characteristics of composite cell sheets of mesenchymal stem cells and endothelial progenitor cells derived from peripheral blood]

Objective

To separate peripheral blood mesenchymal stem cells (PBMSC) and peripheral blood endothelial progenitor cells (PBEPC) from peripheral blood, and investigate the biological characteristics of composite cell sheets of PBMSC and PBEPC.

Methods

The peripheral blood of healthy adult New Zealand white rabbits was extracted and PBMSC and PBEPC were separated by density gradient centrifugation. Morphological observation and identification of PBMSC and PBEPC were performed. The 3rd generation of PBMSC and PBEPC were used to construct a composite cell sheet at a ratio of 1∶1, and the 3rd generation of PBMSC was used to construct a single cell sheet as control. The distributions of cells in two kinds of cell sheets were observed by HE staining. In addition, the expression of alkaline phosphatase (ALP), osteocalcin (OCN), and vascular endothelial growth factor (VEGF) in the supernatants of cell sheets were observed by ELISA at 1, 5, and 10 days after osteogenic induction.

Results

The morphology of PBMSC was spindle-shaped or polygonal, and PBMSC had good abilities of osteogenic and adipogenic differentiation. The morphology of PBEPC was paved stone-like, and the tube-forming test of PBEPC was positive. Two kinds of cell sheets were white translucent. The results of HE staining showed that the composite cell sheet had more cell layers and higher cell density than the single cell sheet. The expressions of ALP, OCN, and VEGF in the supernatant of the two groups of cell sheets increased with the time of induction. The expression of OCN in the group of composite cell sheet was significantly higher than that in the group of single cell sheet on the 5th and 10th day, ALP on the 10th day was significantly higher than that in the group of single cell sheet, VEGF expression on the 1st, 5th, and 10th day was significantly higher than that in the group of single cell sheet, all showing significant differences ( P<0.05), and there was no significant difference between the two groups at other time points ( P>0.05).

Conclusion

PBMSC have stable differentiation ability, and they have good application prospects because of their minimally invasive access. Composite cell membranes constructed by co-culture of two kinds of cells and induction of membrane formation provides a new idea and exploration for tissue defect repair.

Human Urine-Derived Stem Cell Differentiation to Endothelial Cells with Barrier Function and Nitric Oxide Production

Endothelial cells (ECs) play a key role in revascularization within regenerating tissue. Stem cells are often used as an alternative cell source when ECs are not available. Several cell types have been used to give rise to ECs, such as umbilical cord vessels, or differentiated from somatic stem cells, embryonic, or induced pluripotent stem cells. However, the latter carry the potential risk of chronic immune rejection and oncogenesis. Autologous endothelial precursors are an ideal resource, but currently require an invasive procedure to obtain them from the patient's own blood vessels or bone marrow. Thus, the goal of this study was to determine whether urine-derived stem cells (USCs) could differentiate into functional ECs in vitro. Urine-derived cells were then differentiated into cells of the endothelial lineage using endothelial differentiation medium for 14 days. Changes in morphology and ultrastructure, and functional endothelial marker expression were assessed in the induced USCs in vitro. Grafts of the differentiated USCs were then subcutaneously injected into nude mice. Induced USCs expressed significantly higher levels of specific markers of ECs (CD31, vWF, eNOS) in vitro and in vivo, compared to nondifferentiated USCs. In addition, the differentiated USC formed intricate tubular networks and presented similar tight junctions, and migration and invasion ability, as well as ability to produce nitric oxide (NO) compared to controls. Using USCs as autologous EC sources for vessel, tissue engineering strategies can yield a sufficient number of cells via a noninvasive, simple, and low-cost method suitable for rapid clinical translation. Stem Cells Translational Medicine 2018 Stem Cells Translational Medicine 2018;7:686-698.

Derivation and Identification of Motor Neurons from Human Urine-Derived Induced Pluripotent Stem Cells

Induced pluripotent stem cells (iPSCs) have provided new opportunities for motor neuron disease (MND) modeling, drug screening, and cellular therapeutic development. Among the various types of iPSCs, urine-derived iPSCs have become a promising source of stem cells because they can be safely and noninvasively isolated and easily reprogrammed. Here, for the first time, we differentiated urine-derived iPSCs (urine-iPSCs) into motor neurons (MNs) and compared the capacity of urine-iPSCs and cord-blood-derived iPSCs (B-iPSCs) to differentiate into MNs. With the use of small molecules, mature MNs were generated from urine-iPSCs as early as 26 days in culture. Furthermore, in coculture with muscle cells, MNs projected long axons and formed neuromuscular junctions (NMJs). Immunofluorescence and PCR confirmed the expression levels of both MN and NMJ markers. The comparison of the ratios of positive labeling for MN markers between urine-iPSCs and B-iPSCs demonstrated that the differentiation potentials of these cells were not significantly different. The abovementioned results indicate that urine-iPSCs are a new, promising source of stem cells for MND modeling and further cellular therapeutic development.

Cell therapy for the treatment of sepsis and acute respiratory distress syndrome

Sepsis and acute respiratory distress syndrome (ARDS) are life threating diseases with high mortality and morbidity in all the critical care units around the world. After decades of research, and numerous pre-clinical and clinical trials, sepsis and ARDS remain without a specific and effective pharmacotherapy and essentially the management remains supportive. In the last years cell therapies gained potential as a therapeutic treatment for ARDS and sepsis. Based on numerous pre-clinical studies, there is a growing evidence of the potential benefits of cell based therapies for the treatment of sepsis and ARDS. Several cell types are used in the last years for the treatment of both syndromes showing high efficiency. Embryonic stem cells (ESC), multipotent stem (or stromal) cells (MSC) and epithelial progenitors cells (EpPC) have been used for both diseases. Nowadays, the major part of the pre-clinical studies are using MSC, however other relevant groups are also using induced pluripotent stem cells (iPSC) for the treatment of both syndromes and alveolar type II cells for ARDS treatment. Numerous questions need further study including: determining the best source for the progenitor cells isolation, their large scale production and cryopreservation. Also, the heterogeneity of patients with sepsis and ARDS is massive, and establish a target population or the stratification of the patients will help us to determine better the therapeutic effect of these cell therapies. In this review we are going to describe briefly the different cell types, their potential sources and characteristics and mechanism of action. Here, also we elucidate the results of several pre-clicinical and clinical studies in ARDS and in sepsis and the future directions of these studies.

Recent advances in our understanding of the mechanisms of late lung development and bronchopulmonary dysplasia

The objective of lung development is to generate an organ of gas exchange that provides both a thin gas diffusion barrier and a large gas diffusion surface area, which concomitantly generates a steep gas diffusion concentration gradient. As such, the lung is perfectly structured to undertake the function of gas exchange: a large number of small alveoli provide extensive surface area within the limited volume of the lung, and a delicate alveolo-capillary barrier brings circulating blood into close proximity to the inspired air. Efficient movement of inspired air and circulating blood through the conducting airways and conducting vessels, respectively, generates steep oxygen and carbon dioxide concentration gradients across the alveolo-capillary barrier, providing ideal conditions for effective diffusion of both gases during breathing. The development of the gas exchange apparatus of the lung occurs during the second phase of lung development-namely, late lung development-which includes the canalicular, saccular, and alveolar stages of lung development. It is during these stages of lung development that preterm-born infants are delivered, when the lung is not yet competent for effective gas exchange. These infants may develop bronchopulmonary dysplasia (BPD), a syndrome complicated by disturbances to the development of the alveoli and the pulmonary vasculature. It is the objective of this review to update the reader about recent developments that further our understanding of the mechanisms of lung alveolarization and vascularization and the pathogenesis of BPD and other neonatal lung diseases that feature lung hypoplasia.

Exosomes from iPSCs Delivering siRNA Attenuate Intracellular Adhesion Molecule-1 Expression and Neutrophils Adhesion in Pulmonary Microvascular Endothelial Cells

The pro-inflammatory activation of pulmonary microvascular endothelial cells resulting in continuous expression of cellular adhesion molecules, and subsequently recruiting primed neutrophils to form a firm neutrophils-endothelium (PMN-EC) adhesion, has been examined and found to play a vital role in acute lung injury (ALI). RNA interference (RNAi) is a cellular process through harnessing a natural pathway silencing target gene based on recognition and subsequent degradation of specific mRNA sequences. It opens a promising approach for precision medicine. However, this application was hampered by many obstacles, such as immunogenicity, instability, toxicity problems, and difficulty in across the biological membrane. In this study, we reprogrammed urine exfoliated renal epithelial cells into human induced pluripotent stem cells (huiPSCs) and purified the exosomes (Exo) from huiPSCs as RNAi delivery system. Through choosing the episomal system to deliver transcription factors, we obtained a non-integrating huiPSCs. Experiments in both vitro and vivo demonstrated that these huiPSCs possess the pluripotent properties. The exosomes of huiPSCs isolated by differential centrifugation were visualized by transmission electron microscopy (TEM) showing a typical exosomal appearance with an average diameter of 122 nm. Immunoblotting confirmed the presence of the typical exosomal markers, including CD63, TSG 101, and Alix. Co-cultured PKH26-labeled exosomes with human primary pulmonary microvascular endothelial cells (HMVECs) confirmed that they could be internalized by recipient cells at a time-dependent manner. Then, electroporation was used to introduce siRNA against intercellular adhesion molecule-1 (ICAM-1) into exosomes to form an Exo/siRNA compound. The Exo/siRNA compound efficiently delivered the target siRNA into HMVECs causing selective gene silencing, inhibiting the ICAM-1 protein expression, and PMN-EC adhesion induced by lipopolysaccharide (LPS). These data suggest that huiPSCs exosomes could be used as a natural gene delivery vector to transport therapeutic siRNAs for alleviating inflammatory responses in recipient cells.

Evaluation of Therapeutic Oligonucleotides for Familial Amyloid Polyneuropathy in Patient-Derived Hepatocyte-Like Cells

Familial amyloid polyneuropathy (FAP) is caused by mutations of the transthyretin (TTR) gene, predominantly expressed in the liver. Two compounds that knockdown TTR, comprising a small interfering RNA (siRNA; ALN-TTR-02) and an antisense oligonucleotide (ASO; IONIS-TTRRx), are currently being evaluated in clinical trials. Since primary hepatocytes from FAP patients are rarely available for molecular analysis and commercial tissue culture cells or animal models lack the patient-specific genetic background, this study uses primary cells derived from urine of FAP patients. Urine-derived cells were reprogrammed to induced pluripotent stem cells (iPSCs) with high efficiency. Hepatocyte-like cells (HLCs) showing typical hepatic marker expression were obtained from iPSCs of the FAP patients. TTR mRNA expression of FAP HLCs almost reached levels measured in human hepatocytes. To assess TTR knockdown, siTTR1 and TTR-ASO were introduced to HLCs. A significant downregulation (>80%) of TTR mRNA was induced in the HLCs by both oligonucleotides. TTR protein present in the cell culture supernatant of HLCs was similarly downregulated. Gene expression of other hepatic markers was not affected by the therapeutic oligonucleotides. Our data indicate that urine cells (UCs) after reprogramming and hepatic differentiation represent excellent primary human target cells to assess the efficacy and specificity of novel compounds.