Search Results (208)

Diabetes mellitus, both type 1 (T1D) and type 2 (T2D), has become the epidemic of the century and a major public health concern given its rising prevalence and the increasing adoption of a sedentary lifestyle globally. This multifaceted disease is characterized by impaired pancreatic beta cell function and insulin resistance (IR) in peripheral organs, namely the liver, skeletal muscle, and adipose tissue. Additional insulin target tissues, including cardiomyocytes and neuronal cells, are also affected. The advent of stem cell research has opened new avenues for tackling this disease, particularly through the regeneration of insulin target cells and the establishment of disease models for further investigation. Human-induced pluripotent stem cells (iPSCs) have emerged as a valuable resource for generating specialized cell types, such as hepatocytes, myocytes, adipocytes, cardiomyocytes, and neuronal cells, with diverse applications ranging from drug screening to disease modeling and, importantly, treating IR in T2D. This review aims to elucidate the significant applications of iPSC-derived insulin target cells in studying the pathogenesis of insulin resistance and T2D. Furthermore, recent differentiation strategies, protocols, signaling pathways, growth factors, and advancements in this field of therapeutic research for each specific iPSC-derived cell type are discussed. Full article

Tetranectin (TN) is a plasminogen-binding protein found in human serum. Although it has been suggested to be closely related to various stem cell differentiation, including myogenesis, the role of TN in muscle development remains unclear. In this study, we identified TN as an anti-myogenic factor during the differentiation of C2C12 satellite cells. The exogenous supplementation of TN inhibited myogenic differentiation, whereas differentiation was significantly enhanced in the TN-depleted medium. Epigallocatechin-3-gallate (EGCG), a catechin abundant in green tea, significantly enhanced myogenic differentiation by reducing TN levels in the medium and downregulating TN gene expression during the differentiation process. These results demonstrate that EGCG promotes myogenesis by inhibiting TN at both the transcriptional and functional levels, highlighting TN as a promising therapeutic target for muscle regeneration disorders. Full article

Skeletal muscle regeneration requires a reliable source of myogenic progenitor cells capable of forming new fibers and creating a self-renewing satellite cell pool. Human induced pluripotent stem cell (hiPSC)-derived teratomas have emerged as a novel in vivo platform for generating skeletal myogenic progenitors, although in vivo studies to date have provided only an early single-time-point snapshot. In this study, we isolated a specific population of CD82⁺ ERBB3⁺ NGFR⁺ cells from human iPSC-derived teratomas and verified their long-term in vivo regenerative capacity following transplantation into NSG-mdx^4Cv mice. Transplanted cells engrafted, expanded, and generated human Dystrophin⁺ muscle fibers that increased in size over time and persisted stably long-term. A dynamic population of PAX7⁺ human satellite cells was established, initially expanding post-transplantation and declining moderately between 4 and 8 months as fibers matured. MyHC isoform analysis revealed a time-based shift from embryonic to neonatal and slow fiber types, indicating a slow progressive maturation of the graft. We further show that these progenitors can be cryopreserved and maintain their engraftment potential. Together, these findings give insight into the evolution of teratoma-derived human myogenic stem cell grafts, and highlight the long-term regenerative potential of teratoma-derived human skeletal myogenic progenitors. Full article

Background: Duchenne muscular dystrophy (DMD), which affects 1 in 3500 to 5000 newborn boys worldwide, is characterized by progressive skeletal muscle weakness and degeneration. The reduced muscle regeneration capacity presented by patients is associated with increased fibrosis. Satellite cells (SCs) are skeletal muscle stem cells that play an important role in adult muscle maintenance and regeneration. The absence or mutation of dystrophin in DMD is hypothesized to impair SC asymmetric division, leading to cell cycle arrest. Methods: To overcome the limited availability of biopsies from DMD patients, we used our 3D skeletal muscle organoid (SMO) system, which delivers a stable population of myogenic progenitors (MPs) in dormant, activated, and committed stages, to perform SMO cultures using three DMD patient-derived iPSC lines. Results: The results of scRNA-seq analysis of three DMD SMO cultures versus two healthy, non-isogenic, SMO cultures indicate reduced MP populations with constant activation and differentiation, trending toward embryonic and immature myotubes. Mapping our data onto the human myogenic reference atlas, together with primary SC scRNA-seq data, indicated a more immature developmental stage of DMD organoid-derived MPs. DMD fibro-adipogenic progenitors (FAPs) appear to be activated in SMOs. Conclusions: Our organoid system provides a promising model for studying muscular dystrophies in vitro, especially in the case of early developmental onset, and a methodology for overcoming the bottleneck of limited patient material for skeletal muscle disease modeling. Full article

Emerging evidence suggests that the timing of eating and exercise over the course of the day is paramount to metabolism and physical function. This review highlights seminal studies showing that adipocyte AMPKα2 signaling controls circadian adipose tissue–skeletal muscle communication. Day-restricted feeding has been shown to improve exercise performance via adipocyte-specific activation of AMPKα2, which controls fat–muscle crosstalk in a time-of-day dependent manner. This review also discusses corroborating experimental studies designating mesenchymal stem cells as key cellular mediators, showing that exercise in the afternoon leads to better metabolic effects in humans, and illustrating how incorrect timing of food intake leads to leptin resistance and metabolic dysregulation. Multi-omics strategies have shed light on the molecular mechanisms underlying such effects of time, showing the circadian control of metabolic processes across tissues. These results advance our knowledge of chronometabolism and offer exciting temporal intervention treatments for metabolic diseases, such as time-restricted feeding, timed exercise, and chronopharmacological targeting of AMPK. Fat–muscle crosstalk, physical performance, and metabolic health outcomes can possibly be optimized by synchronizing dietary and exercise timing with endogenous circadian rhythms. Full article

Urothelial carcinoma (UC) is a common genitourinary malignancy. Smoking, exposure to arsenic in drinking water, and age can increase the risk of developing UC. Neoadjuvant cisplatin-based chemotherapy prior to radical cystectomy is the standard treatment for the muscle invasive form of UC (MIUC). Tumors of the basal/squamous (Ba/Sq) subtype of MIUC are aggressive, express basal keratins (KRT5, 6, and 14), are associated with squamous differentiation (SD), and frequently develop chemotherapy resistance. The SOX2 transcription factor is a marker of UC stem cells, and its expression is associated with poor overall and disease-free survival. We hypothesized that the attenuation of SOX2 would reduce the expression of basal keratins and increase the chemotherapy response in human UC cells. For this study, we performed lentiviral knockdown (KD) of SOX2 expression in two separate arsenite (As³⁺)-transformed UROtsa (As_I, As_II), 5637, and RT4 cells. Cellular growth and colony-forming ability was inhibited in all UC cell lines after SOX2 KD. We demonstrate that SOX2 KD in the UC cells of the Ba/Sq subtype (As_I, As_II, 5637) decreased the expression of stem-associated proteins, oncoproteins, and basal keratins. Additionally, there was an induction of several luminal markers and enhanced cisplatin sensitivity following the repression of SOX2. Lastly, proteomics revealed reductions in lipid-, cholesterol-, and interferon-signaling pathways after SOX2 KD. This study provides a better understanding of the regulation of key genes responsible for defining the Ba/Sq subtype of UC and demonstrates that the inhibition of SOX2 improves chemotherapy response in UC. Full article

Cardiomyopathies are a heterogeneous group of heart muscle diseases that can lead to heart failure, arrhythmias, and sudden cardiac death. Traditional animal models and in vitro systems have limitations in replicating the complex pathology of human cardiomyopathies. Induced pluripotent stem cells (iPSCs) offer a transformative platform by enabling the generation of patient-specific cardiomyocytes, thus opening new avenues for disease modeling, drug discovery, and regenerative therapy. This process involves reprogramming somatic cells into iPSCs and subsequently differentiating them into functional cardiomyocytes, which can be characterized using techniques such as electrophysiology, contractility assays, and gene expression profiling. iPSC-derived cardiomyocyte (iPSC-CM) platforms are also being explored for drug screening and personalized medicine, including high-throughput testing for cardiotoxicity and the identification of patient-tailored therapies. While iPSC-CMs already serve as valuable models for understanding disease mechanisms and screening drugs, ongoing advances in maturation and bioengineering are bringing iPSC-based therapies closer to clinical application. Furthermore, the integration of multi-omics approaches and artificial intelligence (AI) is enhancing the predictive power of iPSC models. iPSC-based technologies are paving the way for a new era of personalized cardiology, with the potential to revolutionize the management of cardiomyopathies through patient-specific insights and regenerative strategies. Full article

Stress urinary incontinence (SUI) is characterized by the involuntary leakage of urine during activities that increase intra-abdominal pressure. The management of SUI encompasses surgical treatments, such as colposuspension and sling procedures, and nonsurgical ones that involve pelvic floor muscle treatment, behavioral therapies, as well as pharmacological interventions. By exploring nonsurgical options initially, individuals have the opportunity to address the root causes of stress urinary incontinence and strengthen pelvic floor muscles. Background/Objectives: This article delves into the conservative measures in managing SUI among women and the options of minimally invasive strategies for SUI, such as the injection of platelet-rich plasma, stem cells, bulking agents, and laser and radiofrequency therapy. Methods: A search of the literature from 2010 until January 2024 was carried out on PubMed, Cochrane Library, and Web of Science research databases. Results: A total of 34 studies on human females assessing the roles of platelet-rich plasma, laser and radiofrequency therapy, bulking agents, and stem cell therapy were included. Conclusions: The shortcoming of most conservative techniques seems to be represented by the temporary effects and the necessity of repeated treatments. To establish effective medical techniques, adopting more standardized procedures and conducting comprehensive randomized controlled trials is imperative. Full article

HDAC11, the only class IV histone deacetylase, primarily functions as a fatty acid deacylase and has been implicated in metabolic regulation, cancer stemness, and muscle regeneration. However, its role in cardiac mesenchymal stem cells (CMSCs) remains unexplored. To investigate the effects of HDAC11 overexpression on the gene regulatory networks in CMSCs, we treated mouse CMSCs with an adenoviral vector encoding human HDAC11 (Ad-HDAC11) versus adenoviral GFP (Ad-GFP) as a control. Gene expression and pathway enrichment were assessed using RNA sequencing (RNA-seq), and HDAC11 overexpression was validated at the RNA and protein levels through qRT-PCR and Western blot. RNA-seq and Gene Ontology (GO) analysis revealed that HDAC11 overexpression activated cell cycle pathways while suppressing nucleotide transport and phagolysosome-related processes. Furthermore, pHH3 protein level was increased, suggested enhanced proliferation in HDAC11-overexpressed CMSCs. qRT-PCR also confirmed the downregulation of GM11266, a long non-coding RNA, in HDAC11-overexpressing CMSCs. In summary, HDAC11 overexpression promotes transcriptional reprogramming, cell cycle progression, and CMSC proliferation, underscoring its potential role in regulating CMSC growth and division. Full article

Mammary intraductal macrophages (foam cells) in humans are the most commonly encountered cells in spontaneous breast nipple discharge, nipple aspirate fluid, and ductal lavage, yet their origin remains unproven. These cells, in both humans and murine model systems, increase in pregnancy, pseudopregnancy, and other conditions like proliferative fibrocystic disease and intraductal neoplasia, ductal carcinoma in situ (DCIS), where there is intraductal ectasia and obstruction. Previous immunocytochemical studies with macrophage (CD68, lysozyme), epithelial (cytokeratin, estrogen receptor), and myoepithelial (smooth muscle actin, CALLA, maspin) markers have indicated that intraductal foam cells are of macrophage lineage. These foam cells engage in phagocytosis of both endogenous and exogenous substances present within the ducts and are not proliferative. Although it has been suggested that foam cells could derive from tissue-specific and niche-specific precursors or circulating monocytes, to date no experimental nor clinical studies have provided direct proof of their origin. In this study, we provide evidence in both human and murine bone marrow transplant studies that intraductal foam cells are bone marrow-derived. We first studied a registry of sex-mismatched bone marrow transplant recipients who later in life had undergone breast biopsies for either proliferative fibrocystic disease, DCIS, or gynecomastia, and studied these biopsies by XY chromosome fluorescence in situ hybridization (FISH) and informative microsatellite polymorphic markers. The intraductal foam cells were of bone marrow donor-origin. Then, in the experimental bone marrow transplant murine studies, donor marrow from female ROSA26 containing the lacZ reporter were transplanted into either irradiated female recipient transgenic mice carrying the highly penetrant MMTV-pymT or FVB/N background mice, where induced pluripotent stem (iPS) cells derived from tail vein fibroblasts of FVB/N-Tg(MMTV-PyVT)634Mul/J mice were subsequently injected into their mammary fat pads. In all of the transplanted recipient mice, the intraductal foam cells expressed the β-galactosidase (lacZ) reporter and also co-expressed markers of myeloid–macrophage lineage. The number of donor-derived intraductal foam cells increased in pseudopregnancy 5-fold and in intraductal neoplasia 10-fold. Although macrophages of different origins and lineages are undoubtedly present within both the murine and human breasts, those macrophages that qualify as phagocytic intraductal foam cells are bone marrow-derived. Full article

Emery–Dreifuss muscular dystrophy type 1 (EDMD1) is a rare genetic disease caused by mutations in the EMD gene, which encodes the nuclear envelope protein emerin. Despite understanding the genetic basis of the disease, the molecular mechanism underlying muscle and cardiac pathogenesis remains elusive. Progress is restricted by the limited availability of patient-derived samples; therefore, there is an urgent need for human-specific cellular models. In this study, we present the generation and characterization of induced pluripotent stem cell (iPSC) lines derived from EDMD1 patients carrying EMD mutations that lead to truncated or absent emerin, together with iPSCs from healthy donor. The patient-specific iPSCs exhibit stable karyotypes, maintain appropriate morphology, express pluripotency markers, and demonstrate the ability to differentiate into three germ layers. To model EDMD1, these iPSCs were differentiated into myogenic progenitors, myoblasts, and multinucleated myotubes, which represent all stages of myogenesis. Each developmental stage was validated by the presence of stage-specific markers, ensuring the accuracy of the model. We present the first iPSC-based in vitro platform that captures the complexity of EDMD1 pathogenesis during myogenesis. This model can significantly contribute to understanding disease mechanisms and develop the targeted therapeutic strategies for EDMD1. Full article

Porcine latissimus dorsi muscle (LDM) is a crucial source of pork products. Meat quality indicators, such as the proportion of muscle fibers and intramuscular fat (IMF) deposition, vary during the growth and development of pigs. Numerous studies have highlighted the heterogeneous nature of skeletal muscle, with phenotypic differences reflecting variations in cellular composition and transcriptional profiles. This study investigates the cellular-level transcriptional characteristics of LDM in large white pigs at two growth stages (170 days vs. 245 days) using single-nucleus RNA sequencing (snRNA-seq). We identified 56,072 cells across 12 clusters, including myofibers, fibro/adipogenic progenitor (FAP) cells, muscle satellite cells (MUSCs), and other resident cell types. The same cell types were present in the LDM at both growth stages, but their proportions and states differed. A higher proportion of FAPs was observed in the skeletal muscle of 245-day-old pigs. Additionally, these cells exhibited more active communication with other cell types compared to 170-day-old pigs. For instance, more interactions were found between FAPs and pericytes or endothelial cells in 245-day-old pigs, including collagen and integrin family signaling. Three subclasses of FAPs was identified, comprising FAPs_COL3A1⁺, FAPs_PDE4D⁺, and FAPs_EBF1⁺, while adipocytes were categorized into Ad_PDE4D⁺ and Ad_DGAT2⁺ subclasses. The proportions of these subclasses differed between the two age groups. We also constructed differentiation trajectories for FAPs and adipocytes, revealing that FAPs in 245-day-old pigs differentiated more toward fibrosis, a characteristic reminiscent of the high prevalence of skeletal muscle fibrosis in aging humans. Furthermore, the Ad_PDE4D⁺ adipocyte subclass, predominant in 245-day-old pigs, originated from FAPs_PDE4D⁺ expressing the same gene, while the Ad_DGAT2⁺ subclass stemmed from FAPs_EBF1⁺. In conclusion, our study elucidates transcriptional differences in skeletal muscle between two growth stages of pigs and provides insights into mechanisms relevant to pork meat quality and skeletal muscle diseases. Full article

The global issue of aging populations has become increasingly prominent, thus the research and development for anti-aging therapies to assure longevity as well as to ameliorate age-related complications is put high on the agenda. The young humoral milieu has been substantiated to impart youthful characteristics to aged cells or organs. Extracellular vesicles (EVs) are a heterogeneous group of cell-derived membrane-limited structures that serve as couriers of proteins and genetic material to regulate intercellular communication. Of note, EVs appeared to be an indispensable component of young blood in prolonging lifespans, and circulating EVs have been indicated to mediate the beneficial effect of a young milieu on aging. Human umbilical cord mesenchymal stem cell-derived EVs (HUCMSC-EVs), isolated from the youngest adult stem cell source, are speculated to reproduce the function of circulating EVs in young blood and partially revitalize numerous organs in old animals. Robust evidence has suggested HUCMSC-EVs as muti-target therapeutic agents in combating aging and alleviating age-related degenerative disorders. Here, we provide a comprehensive overview of the anti-aging effects of HUCMSC-EVs in brain, heart, vasculature, kidney, muscle, bone, and other organs. Furthermore, we critically discuss the current investigation on engineering strategies of HUCMSC-EVs, intending to unveil their full potential in the field of anti-aging research. Full article

In general, the nerve cells of the peripheral nervous system regenerate normally within a certain period after the physical damage of their axon. However, when peripheral nerves are transected by trauma or tissue extraction for cancer treatment, spontaneous nerve regeneration cannot occur. Therefore, it is necessary to perform microsurgery to connect the transected nerve directly or insert a nerve conduit to connect it. In this study, we applied human tonsillar mesenchymal stem cell (TMSC)-derived Schwann cell-like cells (TMSC-SCs) to facilitate nerve regeneration and prevent muscle atrophy after neurorrhaphy. The TMSC-SCs were manufactured in a good manufacturing practice facility and termed neuronal regeneration-promoting cells (NRPCs). A rat model of peripheral nerve injury (PNI) was generated and a mixture of NRPCs and fibrin glue was transplanted into the injured nerve after neurorrhaphy. The application of NRPCs and fibrin glue led to the efficient induction of sciatic nerve regeneration, with the sparing of gastrocnemius muscles and neuromuscular junctions. This sparing effect of NRPCs toward neuromuscular junctions might prevent muscle atrophy after neurorrhaphy. These results suggest that a mixture of NRPCs and fibrin glue may be a therapeutic candidate to enable peripheral nerve and muscle regeneration in the context of neurorrhaphy in patients with PNI. Full article

Idiopathic pulmonary fibrosis (IPF) is the most common type of fibrosis in lungs, characterized as a chronic and progressive interstitial lung disease involving pathological findings of fibrosis with a median survival of 3 years. Despite the knowledge accumulated regarding IPF from basic and clinical research, an effective medical therapy for the condition remains to be established. Thus, it is necessary for further research, including stem cell therapy, which will provide new insights into and expectations for IPF treatment. Recently, it has been reported that one of the new therapeutic candidates for IPF is adipose-derived mesenchymal stem cells (ADSCs), which have several benefits, such as easy accessibility and minimal morbidity compared to bone marrow-derived mesenchymal stem cells. Therefore, we investigated the possibility of ADSCs as a therapeutic candidate for IPF. Using human lung fibroblasts (LFs) from IPF patients, we demonstrated that human IPF LFs cocultured with ADSCs led to reduced fibrosis-related genes. Further analysis revealed that ADSCs prevented the activation of the ERK signaling pathway in IPF LFs via the upregulation of protein tyrosine phosphatase receptor-type R (PTPRR), which negatively regulates the ERK signaling pathway. Moreover, we demonstrated that intravascular administration of ADSCs improved the pathogenesis of bleomycin-induced pulmonary fibrosis with reduced collagen deposition in histology and hydroxyproline quantification and collagen markers such as the gene expression of types I and III collagen and α-smooth muscle actin (α-SMA) in a murine model. ADSC transfer was also investigated in a humanized mouse model of lung fibrosis induced via the infusion of human IPF LFs, because the bleomycin installation model does not fully recapitulate the pathogenesis of IPF. Using the humanized mouse model, we found that intravascular administration of ADSCs also improved fibrotic changes in the lungs. These findings suggest that ADSCs are a promising therapeutic candidate for IPF. Full article