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Frontiers in Cell and Developmental... 2024Mammalian germ cells are derived from primordial germ cells (PGCs) and ensure species continuity through generations. Unlike irreversible committed mature germ cells,...
Mammalian germ cells are derived from primordial germ cells (PGCs) and ensure species continuity through generations. Unlike irreversible committed mature germ cells, migratory PGCs exhibit a latent pluripotency characterized by the ability to derive embryonic germ cells (EGCs) and form teratoma. Here, we show that inhibition of p38 mitogen-activated protein kinase (MAPK) by chemical compounds in mouse migratory PGCs enables derivation of chemically induced Embryonic Germ-like Cells (cEGLCs) that do not require conventional growth factors like LIF and FGF2/Activin-A, and possess unique naïve pluripotent-like characteristics with epiblast features and chimera formation potential. Furthermore, cEGLCs are regulated by a unique PI3K-Akt signaling pathway, distinct from conventional naïve pluripotent stem cells described previously. Consistent with this notion, we show by performing analysis that inhibition of p38 MAPK in organ culture supports the survival and proliferation of PGCs and also potentially reprograms PGCs to acquire indefinite proliferative capabilities, marking these cells as putative teratoma-producing cells. These findings highlight the utility of our model in mimicking teratoma formation, thereby providing valuable insights into the cellular mechanisms underlying tumorigenesis. Taken together, our research underscores a key role of p38 MAPK in germ cell development, maintaining proper cell fate by preventing unscheduled pluripotency and teratoma formation with a balance between proliferation and differentiation.
PubMed: 38911025
DOI: 10.3389/fcell.2024.1410177 -
APL Bioengineering Jun 2024Previous lung-on-chip devices have facilitated significant advances in our understanding of lung biology and pathology. Here, we describe a novel lung-on-a-chip model in...
Previous lung-on-chip devices have facilitated significant advances in our understanding of lung biology and pathology. Here, we describe a novel lung-on-a-chip model in which human induced pluripotent stem cell-derived alveolar epithelial type II cells (iAT2s) form polarized duct-like lumens alongside engineered perfused vessels lined with human umbilical vein endothelium, all within a 3D, physiologically relevant microenvironment. Using this model, we investigated the morphologic and signaling consequences of the KRAS mutation, a commonly identified oncogene in human lung adenocarcinoma (LUAD). We show that expression of the mutant KRAS isoform in iAT2s leads to a hyperproliferative response and morphologic dysregulation in the epithelial monolayer. Interestingly, the mutant epithelia also drive an angiogenic response in the adjacent vasculature that is mediated by enhanced secretion of the pro-angiogenic factor soluble uPAR. These results demonstrate the functionality of a multi-cellular platform capable of modeling mutation-specific behavioral and signaling changes associated with lung adenocarcinoma.
PubMed: 38911024
DOI: 10.1063/5.0207228 -
Biochemistry and Biophysics Reports Sep 2024The three-dimensional (3D) kidney organoid is a breakthrough model for recapitulating renal morphology and function , which is grown from stem cells and resembles... (Review)
Review
The three-dimensional (3D) kidney organoid is a breakthrough model for recapitulating renal morphology and function , which is grown from stem cells and resembles mammalian kidney organogenesis. Currently, protocols for cultivating this model from induced pluripotent stem cells (iPSCs) and patient-derived adult stem cells (ASCs) have been widely reported. In recent years, scientists have focused on combining cutting-edge bioengineering and bioinformatics technologies to improve the developmental accuracy of kidney organoids and achieve high-throughput experimentation. As a remarkable tool for mechanistic research of the renal system, kidney organoid has both potential and challenges. In this review, we have described the evolution of kidney organoid establishment methods and highlighted the latest progress leading to a more sophisticated kidney transformation research model. Finally, we have summarized the main applications of renal organoids in exploring kidney disease.
PubMed: 38910872
DOI: 10.1016/j.bbrep.2024.101736 -
Circulation Jun 2024Alterations in the buffering of intracellular Ca, for which myofilament proteins play a key role, have been shown to promote cardiac arrhythmia. It is interesting that...
BACKGROUND
Alterations in the buffering of intracellular Ca, for which myofilament proteins play a key role, have been shown to promote cardiac arrhythmia. It is interesting that although studies report atrial myofibrillar degradation in patients with persistent atrial fibrillation (persAF), the intracellular Ca buffering profile in persAF remains obscure. Therefore, we aim to investigate the intracellular buffering of calcium and its potential arrhythmogenic role in persAF.
METHODS
Simultaneous transmembrane fluxes (patch-clamp) and intracellular Ca signaling (fluo-3-acetoxymethyl ester) were recorded in myocytes from right atrial biopsies of sinus rhythm (control) and patients with persAF, alongside human atrial subtype induced pluripotent stem cell-derived cardiac myocytes (iPSC-CMs). Protein levels were quantified by immunoblotting of human atrial tissue and induced pluripotent stem cell-derived cardiac myocytes. Mouse whole heart and atrial electrophysiology was measured on a Langendorff system.
RESULTS
Cytosolic Ca buffering was decreased in atrial myocytes of patients with persAF because of a depleted amount of Ca buffers. In agreement, protein levels of selected Ca binding myofilament proteins, including cTnC (cardiac troponin C), a major cytosolic Ca buffer, were significantly lower in patients with persAF. Small interfering RNA (siRNA)-mediated knockdown of cTnC in induced pluripotent stem cell-derived cardiac myocytes (si-cTnC) phenocopied the reduced cytosolic Ca buffering observed in persAF. Si-cTnC induced pluripotent stem cell-derived cardiac myocytes exhibited a higher predisposition to spontaneous Ca release events and developed action potential alternans at low stimulation frequencies. Last, indirect reduction of cytosolic Ca buffering using blebbistatin in an ex vivo mouse whole heart model increased vulnerability to tachypacing-induced atrial arrhythmia, validating the direct mechanistic link between impaired cytosolic Ca buffering and atrial arrhythmogenesis.
CONCLUSIONS
Our findings suggest that loss of myofilament proteins, particularly reduced cTnC protein levels, causes diminished cytosolic Ca buffering in persAF, thereby potentiating the occurrence of spontaneous Ca release events and AF susceptibility. Strategies targeting intracellular buffering may represent a promising therapeutic lead in AF management.
PubMed: 38910563
DOI: 10.1161/CIRCULATIONAHA.123.066577 -
Neuroscience Jun 2024Mesenchymal stromal cells (MSCs) hold therapeutic potential for neurological disorders, but their impact on neuronal activity remains unclear. We investigated the...
Mesenchymal stromal cells (MSCs) hold therapeutic potential for neurological disorders, but their impact on neuronal activity remains unclear. We investigated the effects of SB623 cells (Notch-1 intracellular domain-transfected MSCs) and parental MSCs on human induced pluripotent stem cell (iPSC)-derived neurons using multi-electrode arrays. SB623 cells significantly increased neuronal activity and oscillation in a dose-dependent manner, surpassing astrocytes in promoting network bursts. Strikingly, glutamatergic neurons showed a rapid increase in activity and bursts compared to GABAergic neurons, suggesting glutamate release from SB623 cells. We confirmed this by finding high glutamate levels in SB623 cell conditioned medium, which were reduced by glutaminase inhibition. Glutamate release was further implicated by the reduced excitability in co-cultures with astrocytes, known glutamate scavengers. Our findings reveal a novel mechanism for MSCs: promoting neuronal activity and network formation through tonic glutamate release, with potential implications for MSC-based therapies.
PubMed: 38909673
DOI: 10.1016/j.neuroscience.2024.06.015 -
Stem Cell Research Jun 2024Ten-Eleven Translocation methylcytosine dioxygenase 1 (TET1) is known to play a broad tumor suppressor role through demethylating and activating tumor suppressor genes....
Ten-Eleven Translocation methylcytosine dioxygenase 1 (TET1) is known to play a broad tumor suppressor role through demethylating and activating tumor suppressor genes. TET1 missense mutations are previously reported in many types of leukemia. Here, the human induced pluripotent stem cell line MURAi001-A was generated from skin fibroblasts derived from a 56-year-old female patient carrying the TET1 gene mutation c.4404A > G (p.I1468M), who had a history of ovarian germ cell tumor. The MURAi001-A cell line demonstrated embryonic-like characteristics as it expressed specific stemness markers, differentiated into the three germ layers, and retained normal karyotyping.
PubMed: 38909482
DOI: 10.1016/j.scr.2024.103474 -
Cell & Bioscience Jun 2024Clinical outcome after traumatic brain injury (TBI) is closely associated conditions of other organs, especially lungs as well as degree of brain injury. Even if there... (Review)
Review
Clinical outcome after traumatic brain injury (TBI) is closely associated conditions of other organs, especially lungs as well as degree of brain injury. Even if there is no direct lung damage, severe brain injury can enhance sympathetic tones on blood vessels and vascular resistance, resulting in neurogenic pulmonary edema. Conversely, lung damage can worsen brain damage by dysregulating immunity. These findings suggest the importance of brain-lung axis interactions in TBI. However, little research has been conducted on the topic. An advanced disease model using stem cell technology may be an alternative for investigating the brain and lungs simultaneously but separately, as they can be potential candidates for improving the clinical outcomes of TBI.In this review, we describe the importance of brain-lung axis interactions in TBI by focusing on the concepts and reproducibility of brain and lung organoids in vitro. We also summarize recent research using pluripotent stem cell-derived brain organoids and their preclinical applications in various brain disease conditions and explore how they mimic the brain-lung axis. Reviewing the current status and discussing the limitations and potential perspectives in organoid research may offer a better understanding of pathophysiological interactions between the brain and lung after TBI.
PubMed: 38909262
DOI: 10.1186/s13578-024-01252-2 -
Cell Reports Jun 2024Human induced pluripotent stem cell (hiPSC)-derived intestinal organoids are valuable tools for researching developmental biology and personalized therapies, but their...
Human induced pluripotent stem cell (hiPSC)-derived intestinal organoids are valuable tools for researching developmental biology and personalized therapies, but their closed topology and relative immature state limit applications. Here, we use organ-on-chip technology to develop a hiPSC-derived intestinal barrier with apical and basolateral access in a more physiological in vitro microenvironment. To replicate growth factor gradients along the crypt-villus axis, we locally expose the cells to expansion and differentiation media. In these conditions, intestinal epithelial cells self-organize into villus-like folds with physiological barrier integrity, and myofibroblasts and neurons emerge and form a subepithelial tissue in the bottom channel. The growth factor gradients efficiently balance dividing and mature cell types and induce an intestinal epithelial composition, including absorptive and secretory lineages, resembling the composition of the human small intestine. This well-characterized hiPSC-derived intestine-on-chip system can facilitate personalized studies on physiological processes and therapy development in the human small intestine.
PubMed: 38907996
DOI: 10.1016/j.celrep.2024.114247 -
Cell Reports Jun 2024Planarian flatworms undergo continuous internal turnover, wherein old cells are replaced by the division progeny of adult pluripotent stem cells (neoblasts). How cell...
Planarian flatworms undergo continuous internal turnover, wherein old cells are replaced by the division progeny of adult pluripotent stem cells (neoblasts). How cell turnover is carried out at the organismal level remains an intriguing question in planarians and other systems. While previous studies have predominantly focused on neoblast proliferation, little is known about the processes that mediate cell loss during tissue homeostasis. Here, we use the planarian epidermis as a model to study the mechanisms of cell removal. We established a covalent dye-labeling assay and image analysis pipeline to quantify the cell turnover rate in the planarian epidermis. Our findings indicate that the ventral epidermis is highly dynamic and epidermal cells undergo internalization via basal extrusion, followed by a relocation toward the intestine and ultimately digestion by intestinal phagocytes. Overall, our study reveals a complex homeostatic process of cell clearance that may generally allow planarians to catabolize their own cells.
PubMed: 38906148
DOI: 10.1016/j.celrep.2024.114305 -
Stem Cell Research Jun 2024The X-linked lysosomal storage disorder Fabry disease originates from GLA gene mutations causing α-galactosidase A enzyme deficiency. Here we generated the GLA knockout...
The X-linked lysosomal storage disorder Fabry disease originates from GLA gene mutations causing α-galactosidase A enzyme deficiency. Here we generated the GLA knockout hiPSC line MHHi001-A-15 (GLA-KOhiPSC) as an in vitro Fabry disease model by targeting exon 2 of the GLA gene by CRISPR/Cas9 in the established control hiPSC line MHHi001-A. GLA-KOhiPSCs retained the expression of pluripotency markers, trilineage differentiation potential, as well as normal karyotype and stem cell morphology but lacked α-galactosidase A enzyme activity. The GLA-KOhiPSCs represent a potent resource to not only study the Fabry disease manifestation but also screen for novel treatment options.
PubMed: 38905814
DOI: 10.1016/j.scr.2024.103478