Tissue-derived Stem Cells Research Articles

Comparison of functional characterization of cancer stem cells in different tumor tissues of pseudomyxoma peritonei.

Pseudomyxoma peritonei (PMP) is a rare malignant peritoneal tumor that readily recurs and metastasizes. Studies have shown that cancer stem cells (CSCs) play an important role in tumor recurrence, metastasis, and prognosis. In this study, our aim was to isolate CSCs from various tissues of PMP patients and compare their proliferation, migration, and anti-inflammatory abilities. We identified CSCs subsets with markers CD133+, CD166+, and CD133+/CD166+ at the gene level using single-cell mRNA sequencing (scRNA-seq). Appendiceal CSCs (AC), peritoneal CSCs (PC), and mucous CSCs (MC) were obtained using MACSQuant Tyto sorting technology and FlowSight imaging flow cytometry. The cells were cultured and markers were identified. Finally, the functional phenotypes of the three cell types were compared. CSCs content was highest in the appendiceal tumor tissue and lowest in the mucous tissue. The cell viability rate of the sorted CSCs was above 98%, and the positive rate of CD133+ and CD166+ was 70-80%, and CD133+/CD166+ was about 30%. Among the three types of CSCs, MC had the highest proliferation ability, and TNF-α has the greatest inhibitory effect on AC migration. AC in patients was more inert and anti-inflammatory, whereas abdominal cavity MC and PC were more active. This study revealed the biological characteristics of CSCs in different tumor tissues of patients with PMP, providing a reference for future targeted CSCs therapy.

Dental pulp stem cell‑derived extracellular vesicles loaded with hydrogels promote osteogenesis in rats with alveolar bone defects.

Alveolar bone defects caused by inflammation, trauma and tumors adversely affect periodontal health, causing tooth loosening or dentition defects, thus affecting denture or implant repair. Advancements in tissue engineering technology and stem cell biology have significantly improved the regenerative reconstruction of alveolar bone defects. The multiple trophic activities of extracellular vesicles (EVs) produced by mesenchymal stem cells play important roles in exerting their therapeutic effects. Several studies have reported the role of dental pulp stem cells (DPSCs) in bone regeneration, but the regenerative effects of DPSC‑EVs on alveolar bone defects are unclear. In the present study, the osteogenic effects of DPSC‑EVs on Hertwig's epithelial root sheath (HERS) cells in vitro and their osteoinductive effects in an alveolar bone defect rat model were investigated. The results showed that DPSC‑EVs significantly promoted the expression of osteogenic genes, such as runt‑related transcription factor 2 and alkaline phosphatase, and increased the osteogenic differentiation capability of HERS. These findings suggested that transforming growth factor β1 inhibition decreased DPSC‑EV‑induced Smad, MAPK and ERK phosphorylation in HERS. In vivo, DPSC‑EV‑loaded hydrogels were transplanted into the alveolar sockets of Sprague‑Dawley rats and observed for eight weeks. The new bone grew concentrically in the DPSC‑EV or DPSC‑EV‑loaded hydrogel group, with greater bone mass than that in the control group, and the bone volume/total volume increased notably. The results confirmed the osteogenic and osteoinductive effects of DPSC‑EVs and DPSC‑Exo‑loaded hydrogels on alveolar bone defects. Due to their low immunogenicity, high stability, good biocompatibility and osteogenic propensity, DPSC‑EV‑loaded hydrogels are a safe cell‑free therapeutic approach for defective alveolar bone regeneration.

Stemness in solid malignancies: coping with immune attack.

Immunotherapy has become a key new pillar of cancer treatment, and this has sparked interest in understanding mechanisms of cancer immune evasion. It has long been appreciated that cancers are constituted by heterogeneous populations of tumour cells. This feature is often fuelled by specialized cells that have molecular programs resembling tissue stem cells. Although these cancer stem cells (CSCs) have capacity for unlimited self-renewal and differentiation, it is increasingly evident that some CSCs are capable of achieving remarkable immune resistance. Given that most immunotherapy regiments have overlooked CSC-specific immune-evasive mechanisms, many current treatment strategies often lead to cancer relapse. This Review focuses on advancements in understanding how CSCs in solid tumours achieve their unique immune-evasive properties, enabling them to drive tumour regrowth. Moreover, as cancers often arise from tissue stem cells that acquired oncogenic mutations, we discuss how tissue stem cells undergoing malignant transformation activate intrinsic immune-evasive mechanisms and establish close interactions with suppressive immune cells to escape immune surveillance. In addition, we summarize how in advanced disease stages, CSCs often hijack features of normal stem cells to resist antitumour immunity. Finally, we provide insights in how to design a new generation of cancer immunotherapies to ensure elimination of CSCs.

Anti-tumor effects of ellagic acid and mesenchymal stem cell-conditioned medium on breast cancer cells on the 3D printed PCL/agarose scaffolds

Numerous investigations have demonstrated that natural bioactive compounds, such as flavonoids, exhibit synergistic effects with anticancer agents utilized in clinical practice. Stem cell therapies play a critical role in the domain of oncology; nevertheless, conflicting results have surfaced regarding the potential pro-cancer or anti-cancer characteristics of mesenchymal stem cells. The primary aim of the current investigation was to examine the anticancer efficacy of ellagic acid (EA) alone or in combination with adipose tissue stem cells derived conditioned medium (ADSCs-CM) on human breast cancer cells. In order to overcome the potential effects of two-dimensional (2D) culture, a three-dimensional (3D) printed polycaprolactone (PCL)/agarose scaffold is utilized to evaluate cancer cell behavior. More recently it was reported this scaffold had open and interconnected pores, as well as good water absorption and mechanical properties. Assessment of MCF-7 cancer cell viability was conducted through MTT assay, flow cytometry, cell cycle assay, and quantitative real-time PCR within a 3D cell culture framework. The outcomes revealed a reduction in cancer cell viability across all treatment cohorts in comparison to the control group. Particularly noteworthy was the significantly enhanced effect of the EA and CM combination relative to each component administered individually. Flow cytometry assessment using annexin V/PI staining indicated a decrease in cancer cells, particularly evident in the combination-treated group. Furthermore, the mRNA expression levels of BAX, BCL2, vascular endothelial growth factor (VEGF), and caspase 3 genes were consistent with pathways associated with apoptosis. Consequently, the synergistic anti-proliferative impact of EA in conjunction with ADSCs-CM on MCF-7 cells has been substantiated. These findings have two important implications for breast cancer research; highlight the utility of the PCL/agarose scaffold as a cancer model and suggest new avenues for the development of adjuvant anticancer therapeutic approaches.

Identification and characterization of an enhancer element regulating expression of Cdkn1c (p57 gene).

The mammalian p57 protein is a member of the CIP/KIP family of cyclin-dependent kinase inhibitors and plays an essential role in the development of multiple tissues during embryogenesis as well as in the maintenance of tissue stem cells in adults. Although several transcription factors have been implicated in regulating the p57 gene, cis-elements such as enhancers that regulate its expression have remained ill-defined. Here we identify a candidate enhancer for the mouse p57 gene (Cdkn1c) within an intron of the Kcnq1 locus by 4C-seq analysis in mouse embryonic stem cells (mESCs). Deletion of this putative enhancer region with the CRISPR-Cas9 system or its suppression by CRISPR interference resulted in a marked attenuation of Cdkn1c expression in differentiating mESCs. Our results thus suggest that this region may serve as an enhancer for the p57 gene during early mouse embryogenesis.

Adipose tissue: A treasure trove of stem cells for regenerative medicine

Adipose tissue: A treasure trove of stem cells for regenerative medicine Adipose tissue, commonly known as fat, has long been considered a mere energy reservoir. However, recent discoveries have revolutionized our understanding of this tissue, placing it at the heart of advances in stem cells and regenerative medicine. To shed light on these questions, we will rely on the expertise of Doctors Saja Scherer and Giorgio Pietramaggiori from the Global Medical Institute clinic in Lausanne. These two eminent specialists are at the forefront of research and clinical applications of adipose tissue in regenerative medicine. Dr. Saja Scherer, a renowned plastic surgeon, is recognized for her innovative work on the use of adipose tissue in facial reconstruction and rejuvenation. Her research has contributed to improving fat grafting techniques, thus optimizing results for patients.

Identification and Verification of Key Genes in Colorectal Cancer Liver Metastases Through Analysis of Single-Cell Sequencing Data and TCGA Data

BackgroundColorectal cancer (CRC) is highly prevalent worldwide, with more patients experiencing colorectal cancer liver metastases (CRLM). This study aimed to identify key genes in CRLM through single-cell sequencing data reanalysis and experimental validation.MethodsThe study analyzed single-cell RNA-sequencing (scRNA-seq) data from the Gene Expression Omnibus (GEO) database. Gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were used for gene functional enrichment analysis. The Cancer Genome Atlas (TCGA) data enabled bulk-RNA expression and survival prognosis analysis. Real-time polymerase chain reaction (qPCR) detected mRNA expression, whereas Western blot determined protein levels. Cell function experiments assessed SPARC’s impact on CRC cell behavior.ResultsCluster analysis showed 23 classes among 17 CRLM samples, representing six cell types. A GO and KEGG analysis identified interleukin-1 beta (IL1B), CD2 molecule (CD2), and C-X-C motif chemokine ligand 8 (CXCL8) as significant prognostic factors in CRC. Secreted protein acidic and cysteine rich (SPARC) was one of the top differentially expressed genes (DEGs) in tissue stem cells, confirmed in primary and metastatic lesions. Metastatic lesions showed higher expression of SPARC and CRC stem cell marker leucine-rich repeat containing G protein-coupled receptor 5 (LGR5), which was significantly correlated positively with LGR5 expression. Knockdown of SPARC reduced CRC cell sphere- and colony-formation, invasion, and migration abilities. Overexpression of SPARC significantly increased the malignancy of CRC cells.ConclusionsSeveral key genes were identified in the process of CRLM. In CRLM samples and those corresponding to CRC stem cells, SPARC was significantly upregulated. In the therapy of CRLM, SPARC might be a potential target.

EMF treatment delays mesenchymal stem cells senescence during long-term in vitro expansion by modulating autophagy.

Bone marrow mesenchymal stem cells (BMSCs) are widely used in tissue engineering and regenerative medicine as seed cells. Due to low amount in bone marrow, BMSCs must be expanded and cultured in vitro before application. However, the senescence of stem cell caused by long-term in vitro culture greatly limits its efficacy of transplantation. In this study, we propose an approach based on electromagnetic fields (EMF) treatment to rejuvenate aged BMSCs due to long-term in vitro culture. Aged BMSCs were treated with sinusoidal EMF (50Hz, 0.4mT), and stem cell senescence, cell proliferation, cell differentiation, cell stemness and autophagy level were detected. Additionally, aged BMSCs-laden hydrogels were transplanted into the rat critical-sized calvarial defect with or without EMF treatment. The bone formation was evaluated 8weeks after surgery. Our results indicated that the BMSCs age significantly after long-term in vitro passaging. The self-renew, multiple differentiation capacity, senescence phenotypes and stemness of aged BMSCs are partly reversed by EMF treatment with a frequency of 50Hz and strength of 0.4mT. Moreover, declined autophagy level is observed in BMSCs during long-term in vitro passaging and BMSCs senescence is closely associated with autophagy regulation. Additionally, the mechanistic investigation reveals that EMF treatment rejuvenate senescent BMSCs by enhancing autophagy. Furthermore, EMF treatment significantly promote the therapeutic effect of long-term passaged BMSCs on bone formation in vivo. Overall, our study identifies a practical approach for the rejuvenation of old BMSCs and may provide a promising candidate in tissue engineering and stem cell therapy.

Chromatin remodeling in tissue stem cell fate determination.

Tissue stem cells (TSCs), which reside in specialized tissues, constitute the major cell sources for tissue homeostasis and regeneration, and the contribution of transcriptional or epigenetic regulation of distinct biological processes in TSCs has been discussed in the past few decades. Meanwhile, ATP-dependent chromatin remodelers use the energy from ATP hydrolysis to remodel nucleosomes, thereby affecting chromatin dynamics and the regulation of gene expression programs in each cell type. However, the role of chromatin remodelers in tissue stem cell fate determination is less well understood. In this review, we systematically discuss recent advances in epigenetic control by chromatin remodelers of hematopoietic stem cells, intestinal epithelial stem cells, neural stem cells, and skin stem cells in their fate determination and highlight the importance of their essential role in tissue homeostasis, development, and regeneration. Moreover, the exploration of the molecular and cellular mechanisms of TSCs is crucial for advancing our understanding of tissue maintenance and for the discovery of novel therapeutic targets.

Age-Dependent Differences in Radiation-Induced DNA Damage Responses in Intestinal Stem Cells.

Age at exposure is a critical modifier of the risk of radiation-induced cancer. However, the effects of age on radiation-induced carcinogenesis remain poorly understood. In this study, we focused on tissue stem cells using Lgr5-eGFP-ires-CreERT2 mice to compare radiation-induced DNA damage responses between Lgr5+ and Lgr5- intestinal stem cells. Three-dimensional immunostaining analyses demonstrated that radiation induced apoptosis and the mitotic index more efficiently in adult Lgr5- stem cells than in adult Lgr5+ stem cells but not in infants, regardless of Lgr5 expression. Supporting this evidence, rapid and transient p53 activation occurred after irradiation in adult intestinal crypts but not in infants. RNA sequencing revealed greater variability in gene expression in adult Lgr5+ stem cells than in infant Lgr5+ stem cells after irradiation. Notably, the cell cycle and DNA repair pathways were more enriched in adult stem cells than in infant stem cells after irradiation. Our findings suggest that radiation-induced DNA damage responses in mouse intestinal crypts differ between infants and adults, potentially contributing to the age-dependent susceptibility to radiation carcinogenesis.

Senescent lung-resident mesenchymal stem cells drive pulmonary fibrogenesis through FGF-4/FOXM1 axis

BackgroundIdiopathic pulmonary fibrosis (IPF) is an age-related disease featured with abnormal fibrotic response and compromised lung function. Cellular senescence is now considered as an essential driving mechanism for IPF. Given the poor knowledge of the mechanisms underpinning IPF progression, understanding the cellular processes and molecular pathways is critical for developing effective therapies of IPF.MethodsLung fibrosis was induced using bleomycin in C57BL/6 mice. Cellular senescence was measured by immunofluorescence. The effects of FGF-4 on fibroblast activation markers and signaling molecules were assessed with western blot and qPCR.ResultsWe demonstrated elevated abundance of senescent mesenchymal stem cells (MSCs) in IPF lung tissues, which was tightly correlated with the severity of pulmonary fibrosis in vivo. In addition, senescent MSCs could effectively induce the phenotype of pulmonary fibrosis both in vitro and in vivo. To further confirm how senescent MSCs regulate IPF progression, we demonstrate that FGF-4 is significantly elevated in senescent MSCs, which can induce the activation of pulmonary fibroblasts. In vitro, FGF-4 can activate Wnt signaling in a FOXM1-dependent manner. Inhibition of FOXM1 via thiostrepton effectively impairs FGF-4-induced activation of pulmonary fibroblast and dramatically suppresses the development of pulmonary fibrosis.ConclusionThese findings reveal that FGF-4 plays a crucial role in senescent MSCs-mediated pulmonary fibrogenesis, and suggests that strategies aimed at deletion of senescent MSCs or blocking the FGF-4/FOXM1 axis could be effective in the therapy of IPF.

Exploring herbal preconditioning strategies to improve adipose tissue stem cell therapy efficacy

The application of mesenchymal stem cells (MSCs), specifically those sourced from adipose tissue, has become a focal point in regenerative medicine, showing potential for effective cell therapy. Adipose-derived stem cells (ASCs) offer hope in treating various conditions, yet their viability and integration rates are hindered by the harsh post-transplantation environment marked by inflammation and oxidative stress at the injury site. Lawsonia inermis (henna), Zizyphus spina-christi (Christ's Thorn), and Glycyrrhiza glabra (licorice) are three plants known for their potent antioxidant properties primarily due to their rich content of phenolic compounds and flavonoids. Their potential health benefits make them valuable in both traditional medicine and modern therapeutic applications.This research delves into investigating and contrasting the effects of hydroalcoholic extracts from Lawsonia inermis, Zizyphus spina-christi, and Glycyrrhiza glabra on human adipose tissue stem cells as a pre-conditioning method to alleviate oxidative stress in cell therapy. ASCs were isolated from the pelvic cavity and abdomen, characterized using flow cytometry, and prompted to differentiate into adipogenic and osteogenic lineages. They were then subjected to different concentrations of the aforementioned herbal extracts at varying time frames, followed by MIC and MTT analysis. The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay and the Minimum Inhibitory Concentration (MIC) assay are both used to evaluate the effects of substances on cell viability and cell growth receptively. RNA extraction from ASCs and evaluation of antioxidant gene expression were conducted via Real-time PCR. Flow cytometry data confirmed the presence of MSC markers in the isolated cells from ASCs. Analysis of the herbal extract concentrations revealed that 50 ng/ml had a toxic effect on ASCs, establishing a toxicity reference point for adipose-derived MSCs. Real-time PCR results showcased a notable increase in the expression of antioxidant genes post-preconditioning with hydroalcoholic extracts. This study underscores, for the first time, the safety and lack of toxicity of preconditioning with these extracts for h.ASCs, enhancing their resilience and acclimatization under oxidative stress conditions, potentially boosting the therapeutic potential of h.ASCs. The antioxidant properties of Lawsonia inermis, Zizyphus spina-christi, and Glycyrrhiza glabra may enhance the expression of antioxidant genes (Sod, Gpx and Cata) through several mechanisms, including the activation of transcription factors like Nrf2 (Nuclear factor erythroid 2-related factor 2), which regulates antioxidant gene expression; modulation of signaling pathways such as MAPK (Mitogen-Activated Protein Kinase) and PI3K/Akt (Phosphoinositide 3-kinase/Protein Kinase B); and influencing epigenetic modifications like histone changes or DNA methylation that can alter gene expression. However, further research is necessary to clarify the specific mechanisms by which these plant extracts enhance antioxidant gene expression and to explore their potential therapeutic applications in combating oxidative stress-related diseases. Future proposals should consider more gene investigation and in vivo applications, as well as the long-term effects of pre-conditioning.

Regenerative Medicine: Tissue Engineering and Stem Cell Therapy

Regenerative medicine is an emerging field in the medical sciences, focusing on restoring the function of damaged tissues and organs through innovative techniques such as tissue engineering and stem cell therapy. This article explores key aspects of tissue engineering and stem cell therapy, highlighting their potential to revolutionize traditional medical treatments. Tissue engineering involves the use of specially designed biomaterial scaffolds that support the growth and differentiation of stem cells into functional tissues. Stem cell therapy, on the other hand, offers novel approaches for treating various degenerative diseases and injuries by harnessing the regenerative capabilities of stem cells to repair or replace damaged tissues. The article also examines the major challenges in the development and application of regenerative therapies, including issues of safety, efficacy, and ethics. Furthermore, recent advancements in tissue engineering techniques and stem cell therapies are highlighted, showcasing promising results in clinical trials and preclinical applications. With the potential to transform healthcare paradigms, this field continues to attract the attention of scientists, clinicians, and regulators, although many challenges remain before these techniques can be widely adopted in clinical practice. The article concludes that multidisciplinary collaboration and further research are essential to overcoming existing barriers and maximizing the benefits of these regenerative therapies.

Insights into epithelial-mesenchymal transition from cystic fibrosis rat models

BackgroundMolecular pathways contributing to Cystic Fibrosis pathogenesis remain poorly understood. Epithelial-mesenchymal transition (EMT) has been recently observed in CF lungs and certain CFTR mutation classes may be more susceptible than others. No investigations of EMT processes in CF animal models have been reported. AimThe aim of this study was to assess the expression of EMT-related markers in Phe508del and knockout (CFTR-KO) rat lung tissue and tracheal-derived basal epithelial stem cells, to determine whether CFTR dysfunction can produce an EMT state. MethodThe expression of EMT-related markers in lung tissue and cultured tracheal basal epithelial stem cells from wildtype (WT), Phe508del, and CFTR-KO rats were assessed using qPCR and Western blots. Cell responses were evaluated in the presence of Rho-associated protein kinase (ROCK) inhibitor Y27632, which blocks EMT-pathways, or after treatment with TGFβ1 to stimulate EMT. ResultsDifferent gene expression profiles were observed between Phe508del and CFTR-KO rat models compared to wild type. There was lower expression of type 1 collagen in KO lungs and primary cell cultures, while Phe508del lungs and cells had higher expression, particularly when treated with TGFβ1. The addition of Y27632 rescued changes in EMT related genes in Phe508del cells but not in KO cells. ConclusionOur findings show the first evidence of upregulated EMT pathways in the lungs and airway cells of any CF animal model. Differences in the regulation of the EMT genes and proteins in the Phe508del and CFTR-KO cells suggest that the signalling pathways underlying EMT are CFTR mutation dependent.

Inflammatory Memory in Epidermal Stem Cells - A New Strategy for Recurrent Inflammatory Skin Diseases.

The ability of the skin to "remember" has been a potential mechanism for studying recurrent skin diseases. While it has been thought that the ability to retain past encounters is the prerogative of immune cells, it has recently been discovered that skin tissue stem cells can also take on this task. Epithelial stem cells undergoing inflammation retain their "memory" through epigenetic reprogramming and exhibit rapid epithelialization and epidermal proliferation upon secondary stimulation. This is a non-specific memory modality independent of conventional immune memory, in which histone modifications (acetylation and methylation) and specific transcription factors (AP-1 and STAT3) are involved in the establishment of inflammatory memories, and AIM2/Caspase-1/IL-1β mainly performs the rapid effects of memory. This finding is intriguing for addressing recurrent inflammatory skin diseases, which may explain the fixed-site recurrence of inflammatory skin diseases and develop new therapeutic strategies in the future. However, more research is still needed to decipher the mysteries of memory.

Restauración volumétrica autóloga en pacientes con hemiatrofia adiposa facial

IntroductionFacial lipoatrophy lacks standard clinical criteria for its diagnosis and treatment; however, patients with hemifacial atrophy increase, affecting the mental health of patients who suffer from it. Lipografting has been rescued as an effective and safe treatment option. ObjectiveTo show the results of autologous volumetric restoration in patients with facial adipose hemiatrophy. MethodMulticenter, descriptive, longitudinal and prospective study carried out on 29 patients treated at the Hermanos Ameijeiras Hospital, Cuba and the EIMEC clinic, Spain in the period from July 2018 to July 2023. Both sexes were included, between 19 and 75 years old, with facial asymmetry due to unilateral decrease in subcutaneous cellular tissue. ResultsThe average age was 47.9 years. Women predominated with 79.3%. The most common etiologies were idiopathic, autoimmune and orbital trauma, each accounting for 17.2%. According to the degree of severity, grade II was the highest, with 65.5%, and grade III represented 34.5% of the total. Regarding the amount of grafted adipose tissue, 62.1% of the cases were 31 to 60ml, and 27.6% more than 60ml. According to the number of graft applications, 72.4% required one and 27.6% two applications. 93.1% had no complications and 6.9% reported 50% reabsorption of the graft. Patient satisfaction reached 100% and the results were classified as good in 86.21%; when there was improvement, without complications as well as patient satisfaction. ConclusionAutologous lipotransfer assisted with adipose tissue stem cells is a safe treatment option that offers good results in correcting asymmetry caused by hemifacial lipoatrophy.

Secreted Particle Information Transfer (SPIT) - A Cellular Platform for In Vivo Genetic Engineering.

A multitude of tools now exist that allow us to precisely manipulate the human genome in a myriad of different ways. However, successful delivery of these tools to the cells of human patients remains a major barrier to their clinical implementation. Here we introduce a new cellular approach for in vivo genetic engineering, Secreted Particle Information Transfer (SPIT) that utilizes human cells as delivery vectors for in vivo genetic engineering. We demonstrate the application of SPIT for cell-cell delivery of Cre recombinase and CRISPR-Cas9 enzymes, we show that genetic logic can be incorporated into SPIT and present the first demonstration of human cells as a delivery platform for in vivo genetic engineering in immunocompetent mice. We successfully applied SPIT to genetically modify multiple organs and tissue stem cells in vivo including the liver, spleen, intestines, peripheral blood, and bone marrow. We anticipate that by harnessing the large packaging capacity of a human cell's nucleus, the ability of human cells to engraft into patients' long term and the capacity of human cells for complex genetic programming, that SPIT will become a paradigm shifting approach for in vivo genetic engineering.

Establishing Three-Dimensional Explant Culture of Human Dental Pulp Tissue.

Mesenchymal stem cells in the dental tissue indicate a disposition for differentiation into diverse dental lineages and contain enormous potential as the important means for regenerative medicine in dentistry. Among various dental tissues, the dental pulp contains stem cells, progenitor cells and odontoblasts for maintaining dentin homeostasis. The conventional culture of stem cells holds a limit as the living tissue constitutes the three-dimensional (3D) structure. Recent development in the organoid cultures have successfully recapitulated 3D structure and advanced to the assembling of different types. In the current study, the protocol for 3D explant culture of the human dental pulp tissue has been established by adopting the organoid culture. After isolating dental pulp from human tooth, the intact tissue was placed between two layers for Matrigel with addition of the culture medium. The reticular outgrowth of pre-odontoblast layer continued for a month and the random accumulation of dentin was observed near the end. Electron microscopy showed the cellular organization and in situ development of dentin, and immunohistochemistry exhibited the expression of odontoblast and stem cell markers in the outgrowth area. Three-dimensional explant culture of human dental pulp will provide a novel platform for understanding stem cell biology inside the tooth and developing the regenerative medicine.

Kidney organoids: steps towards better organization and function.

Kidney organoids - 3D representations of kidneys made either from pluripotent or tissue stem cells - have been available for well over a decade. Their application could confer notable benefits over longstanding in vivo approaches with the potential for clinically aligned human cells and reduced ethical burdens. They been used, at a proof-of-concept level, in development in disease modeling (including with patient-derived stem cells), and in screening drugs for efficacy/toxicity. They differ from real kidneys: they represent only foetal-stage tissue, in their simplest forms they lack organ-scale anatomical organization, they lack a properly arranged vascular system, and include non-renal cells. Cell specificity may be improved by better techniques for differentiation and/or sorting. Sequential assembly techniques that mimic the sequence of natural development, and localized sources of differentiation-inducing signals, improve organ-scale anatomy. Organotypic vascularization remains a challenge: capillaries are easy, but the large vessels that should serve them are absent from organoids and, even in cultured real kidneys, these large vessels do not survive without blood flow. Transplantation of organoids into hosts results in their being vascularized (though probably not organotypically) and in some renal function. It will be important to transplant more advanced organoids, with a urine exit, in the near future to assess function more stringently. Transplantation of human foetal kidneys, followed by nephrectomy of host kidneys, keeps rats alive for many weeks, raising hope that, if organoids can be produced even to the limited size and complexity of foetal kidneys, they may one day be useful in renal replacement.

Mesenchymal stem cells from adipose tissue prone to lose their stemness associated markers in obesity related stress conditions

Obesity is a health problem characterized by large expansion of adipose tissue. During this expansion, genotoxic stressors can be accumulated and negatively affect the mesenchymal stem cells (MSCs) of adipose tissue. Due to the oxidative stress generated by these genotoxic stressors, senescence phenotype might be observed in adipose tissue MSCs. Senescent MSCs lose their proliferations and differentiation properties and secrete senescence-associated molecules to their niche thus triggering senescence for the rest of the tissue. Accumulation of senescent cells in adipose tissue results in decreased tissue regeneration and functional impairment not only in the close vicinity but also in the other tissues. Here we hypothesized that declined tissue regeneration might be associated with loss of stemness markers in MSCs population. We analyzed the expression of several stemness-associated genes of in vitro cultured MSCs originated from adipose tissue of high-fat diet and normal diet mice models. Since the heterogenous MSCs population covers a small percentage of the pluripotent stem cells, which have roles in proliferation and tissue regeneration, we measured the percentage of these cells via TRA-1-60 pluripotent state antigen. Additionally, by conducting a shotgun proteomic approach using LC-MS/MS, whole cell proteome of the adipose tissue MSCs of high-fat diet and normal diet mice were analyzed and identified proteins were evaluated via gene ontology and PPI network analysis. MSCs of obese mice showed senescent phenotype and altered cell cycle distribution due to a hostile environment with oxidative stress in adipose tissue where they reside. Additionally, the number of pluripotent markers expressing cells declined in the MSC population of the high-fat diet mice. Gene expression analysis evidenced the loss of stemness with a decrease in the expression of stemness-associated genes. Of the proteomic comparison of the normal and the high-fat diet group, MSCs revealed that stemness-associated molecules were decreased while inflammation and senescence-associated phenotypes emerged in obese mice MSCs. Our results showed us that the MSCs of adipose tissue may lose their stemness properties due to obesity-associated stress conditions.