Recent technological advancements on stem cell differentiation induction have been making great progress in stem cell research, regenerative medicine, and therapeutic applications. However, the risk ...of off-target differentiation limits the wide application of stem cell therapy strategies. Here, we report a non-invasive all-optical strategy to induce stem cell differentiation in vitro and in vivo that activates individual target stem cells in situ by delivering a transient 100-ms irradiation of a tightly focused femtosecond laser to a submicron cytoplasmic region of primary adipose-derived stem cells (ADSCs). The ADSCs differentiate to osteoblasts with stable lineage commitment that cannot further transdifferentiate because of simultaneous initiation of multiple signaling pathways through specific Ca2+ kinetic patterns. This method can work in vivo to direct mouse cerebellar granule neuron progenitors to granule neurons in intact mouse cerebellums through the skull. Hence, this optical method without any genetic manipulations or exogenous biomaterials holds promising potential in biomedical research and cell-based therapies.
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•A transient 100-ms non-invasive photoactivation induces stem cell differentiation•Differentiated ADSCs are stable and cannot transdifferentiate further•This non-invasive method works in vivo in intact cerebellums through skull•Simultaneous activation of multiple signaling pathways work for lineage commitment
Tang et al. report an all-optical technology to induce stem cell differentiation by introducing a transient 100-ms photoactivation of a tightly focused femtosecond laser to individual stem cells. This non-invasive method can induce stable differentiation of adipose-derived stem cells in vitro and granule neuron progenitors in intact cerebellums of mice in vivo.
SUMMARY
Proteostasis of the endoplasmic reticulum (ER) is controlled by sophisticated signaling pathways that are collectively called the unfolded protein response (UPR) and are initiated by ...specialized ER membrane‐associated sensors. The evidence that complete loss‐of‐function mutations of the most conserved of the UPR sensors, inositol‐requiring enzyme 1 (IRE1), dysregulates tissue growth and development in metazoans and plants raises the fundamental question as to how IRE1 is connected to organismal growth. To address this question, we interrogated the Arabidopsis primary root, an established model for organ development, using the tractable Arabidopsis IRE1 mutant ire1a ire1b, which has marked root development defects in the absence of exogenous stress. We demonstrate that IRE1 is required to reach maximum rates of cell elongation and root growth. We also established that in the actively growing ire1a ire1b mutant root tips the Target of Rapamycin (TOR) kinase, a widely conserved pro‐growth regulator, is hyperactive, and that, unlike cell proliferation, the rate of cell differentiation is enhanced in ire1a ire1b in a TOR‐dependent manner. By functionally connecting two essential growth regulators, these results underpin a novel and critical role of IRE1 in organ development and indicate that, as cells exit an undifferentiated state, IRE1 is required to monitor TOR activity to balance cell expansion and maturation during organ biogenesis.
Significance Statement
Loss‐of‐function mutations of the conserved UPR regulator IRE1 cause developmental defects under physiological conditions of growth in Arabidopsis. Here, we show that in actively growing ire1a ire1b mutant root tips the TOR kinase, a widely conserved pro‐growth regulator, is hyperactive and that this hyperactivity leads to unbalanced rates of cell differentiation. Therefore, IRE1 is required to monitor TOR activity to balance cell expansion and maturation during root biogenesis.
Osteoblast proliferation and osteogenic differentiation (OGD) are regulated by complex mechanisms. The roles in cell proliferation and OGD of RNA‐binding proteins in the insulin‐like growth factor 2 ...mRNA‐binding protein (IGF2BP) family remain unclear. To elucidate this, we examined the differential expression of IGF2BP2 in OGD and osteoporosis, and the expression profile of IGF2BP2‐binding RNA in vitro. We screened the GEO database for differential expression of IGF2BP in OGD and osteoporosis, and verified the RNAs interacting with IGF2BP2 via RNA immunoprecipitation sequencing assays. The proliferation and OGD of IGF2BP2‐ and serum response factor (SRF)‐treated cells, and their regulatory mechanisms, were examined. IGF2BP2 was differentially expressed in OGD and osteoporosis. The RNA immunoprecipitation sequencing assay identified all of the RNAs that bind with IGF2BP2, and revealed SRF as a target of IGF2BP2. IGF2BP2 and SRF inhibition impaired MC3T3‐E1 cell growth but promoted OGD. The mRNA stability analysis revealed that IGF2BP2 enhanced SRF mRNA stability against degradation. In summary, IGF2BP2 is a potential biomarker and therapeutic target for osteoporosis and OGD.
Osteoblast proliferation and osteogenic differentiation (OGD) are regulated by multiple molecules and complex mechanisms. N6‐methyladenosine (m6A) plays a critical role in the epigenetic regulation of cell proliferation and OGD. The insulin‐like growth factor 2 mRNA‐binding protein (IGF2BP) family of proteins are m6A regulatory factors involved in numerous cellular functions. However, their potential role in cell proliferation and OGD is unclear. In our study, we showed that IGF2BP2 was identified to promote the proliferation of osteoblasts while suppressing OGD through the enhancement of SRF mRNA stability.
Genetic susceptibility of type 2 diabetes and Juxtaposed with another zinc finger protein 1 (Jazf1) has been reported; however, the precise role of Jazf1 in metabolic processes remains elusive. In ...this study, using Jazf1‐knockout (KO)‐induced pluripotent stem cells (iPSC), pancreatic beta cell line MIN6 cells, and Jazf‐1 heterozygous KO (Jazf1+/−) mice, the effect of Jazf1 on gradual differentiation was investigated. We checked the alterations of the genes related with β‐cell specification, maturation, and insulin release against glucose treatment by the gain and loss of the Jazf1 gene in the MIN6 cells. Because undifferentiated Jazf1‐KO iPSC were not significantly different from wild‐type (WT) iPSC, the size and endoderm marker expression after embryoid body (EB) and teratoma formation were investigated. Compared to EB and teratomas formed with WT iPSC, the EB and teratomas from with Jazf1‐KO iPSC were smaller, and in teratomas, the expression of proliferation markers was reduced. Moreover, the expression of the gene sets for β‐cell differentiation and the levels of insulin and C‐peptide secreted by insulin precursor cells were notably reduced in β‐cells differentiated from Jazf1‐KO iPSC compared with those differentiated from WT iPSC. A comparison of Jazf1+/− and WT mice showed that Jazf1+/− mice had lower levels of serum insulin, pancreatic insulin expression, and decreased pancreatic β‐cell size, which resulted in defects in the glucose homeostasis. These findings suggest that Jazf1 plays a pivotal role in the differentiation of β‐cells and glucose homeostasis.
In this study, we uncover the essential role of Juxtaposed with another zinc finger protein 1 (Jazf1) in the differentiation of β‐cells and glucose homeostasis. Induced pluripotent stem cells generated from mice harboring a knockout mutation of Jazf1 led to a reduction in size and capacity for differentiation into insulin‐producing β‐cells as well as a decrease in the insulin produced by the β‐cell mass. In addition, insulin resistance was observed in Jazf1 +/− mice, which disrupted glucose homeostasis.
Diabetes is a systemic disease in which the body cannot regulate the amount of sugar, namely glucose, in the blood. High glucose toxicity has been implicated in the dysfunction of diabetic wound ...healing, following insufficient production (Type 1) or inadequate usage (Type 2) of insulin. Chronic non‐healing diabetic wounds are one of the major complications of both types of diabetes, which are serious concerns for public health and can impact the life quality of patients significantly. In general, diabetic wounds are characterized by deficient chemokine production, an unusual inflammatory response, lack of angiogenesis and epithelialization, and dysfunction of fibroblasts. Increasing scientific evidence from available experimental studies on animal and cell models strongly associates impaired wound healing in diabetes with dysregulated fibroblast differentiation to myofibroblasts, interrupted myofibroblast activity, and inadequate extracellular matrix production. Myofibroblasts play an important role in tissue repair by producing and organizing extracellular matrix and subsequently promoting wound contraction. Based on these studies, hyperglycaemic conditions can interfere with cytokine signalling pathways (such as growth factor‐β pathway) affecting fibroblast differentiation, alter fibroblast apoptosis, dysregulate dermal lipolysis, and enhance hypoxia damage, thus leading to damaged microenvironment for myofibroblast formation, inappropriate extracellular matrix modulation, and weakened wound contraction. In this review, we will focus on the current available studies on the impact of diabetes on fibroblast differentiation and myofibroblast function, as well as potential treatments related to the affected pathways.
Oligodendrocytes in the mammalian brain are continuously generated from NG2 cells throughout postnatal life. However, it is unclear when the decision is made for NG2 cells to self-renew or ...differentiate into oligodendrocytes after cell division. Using a combination of in vivo and ex vivo imaging and fate analysis of proliferated NG2 cells in fixed tissue, we demonstrate that in the postnatal developing mouse brain, the majority of divided NG2 cells differentiate into oligodendrocytes during a critical age-specific temporal window of 3-8 d. Notably, within this time period, damage to myelin and oligodendrocytes accelerated oligodendrocyte differentiation from divided cells, and whisker removal decreased the survival of divided cells in the deprived somatosensory cortex. These findings indicate that during the critical temporal window of plasticity, the fate of divided NG2 cells is sensitive to modulation by external signals.
MicroRNAs (miRNAs) are non-coding single-stranded RNA molecules encoded by endogenous genes, which play a vital role in cell generation, metabolism, apoptosis and stem cell differentiation. ...C3H10T1/2, a mesenchymal cell extracted from mouse embryos, is capable of osteogenic differentiation, adipogenic differentiation and chondrogenic differentiation. Extensive studies have shown that not only miRNAs can directly trigger targeted genes to regulate the tri-lineage differentiation of C3H10T1/2, but it also can indirectly regulate the differentiation by triggering different signaling pathways or various downstream molecules. This paper aims to clarify the regulatory roles of different miRNAs on C3H10T1/2 differentiation, and discussing their balance effect among osteogenic differentiation, adipogenic differentiation and chondrogenic differentiation of C3H10T1/2. We also review the biogenesis of miRNAs, Wnt signaling pathways, MAPK signaling pathways and BMP signaling pathways and provide some specific examples of how these signaling pathways act on C3H10T1/2 tri-lineage differentiation. On this basis, we hope that a deeper understanding of the differentiation and regulation mechanism of miRNAs in C3H10T1/2 can provide a promising therapeutic method for the clinical treatment of bone defects, osteoporosis, osteoarthritis and other diseases.
Predicting drug-induced liver injury in a preclinical setting remains challenging, as cultured primary human hepatocytes (PHHs), pluripotent stem cell-derived hepatocyte-like cells (HLCs), and ...hepatoma cells exhibit poor drug biotransformation capacity. We here demonstrate that hepatic functionality depends more on cellular metabolism and extracellular nutrients than on developmental regulators. Specifically, we demonstrate that increasing extracellular amino acids beyond the nutritional need of HLCs and HepG2 cells induces glucose independence, mitochondrial function, and the acquisition of a transcriptional profile that is closer to PHHs. Moreover, we show that these high levels of amino acids are sufficient to drive HLC and HepG2 drug biotransformation and liver-toxin sensitivity to levels similar to those in PHHs. In conclusion, we provide data indicating that extracellular nutrient levels represent a major determinant of cellular maturity and can be utilized to guide stem cell differentiation to the hepatic lineage.
Tissue regeneration is a multi-step process mediated by diverse cellular hierarchies and states that are also implicated in tissue dysfunction and pathogenesis. Here we leveraged single-cell RNA ...sequencing in combination with in vivo lineage tracing and organoid models to finely map the trajectories of alveolar-lineage cells during injury repair and lung regeneration. We identified a distinct AT2-lineage population, damage-associated transient progenitors (DATPs), that arises during alveolar regeneration. We found that interstitial macrophage-derived IL-1β primes a subset of AT2 cells expressing Il1r1 for conversion into DATPs via a HIF1α-mediated glycolysis pathway, which is required for mature AT1 cell differentiation. Importantly, chronic inflammation mediated by IL-1β prevents AT1 differentiation, leading to aberrant accumulation of DATPs and impaired alveolar regeneration. Together, this stepwise mapping to cell fate transitions shows how an inflammatory niche controls alveolar regeneration by controlling stem cell fate and behavior.
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•Injury-induced IL-1β signaling promotes differentiation of AT2 cells into AT1 cells•AT2 cells differentiate into AT1 cells via cell states of primed AT2 and DATPs•HIF1α signaling controls AT2-DAPT conversion and is essential for AT1 differentiation•Chronic inflammation impairs maturation of AT1 cells
Choi et al. show that inflammatory signals play a crucial role during alveolar regeneration after injury. They define stepwise differentiation trajectories for AT2 cells into AT1 cells via damage-associated transient progenitors (DATPs) and find that unresolved inflammation stalls transition of DATPs into mature AT1 cells.
IL-23 and Th17 cells are key players in tissue immunosurveillance and are implicated in human immune-mediated diseases. Genome-wide association studies have shown that the IL23R R381Q gene variant ...protects against psoriasis, Crohn's disease and ankylosing spondylitis. We investigated the immunological consequences of the protective IL23R R381Q gene variant in healthy donors. The IL23R R381Q gene variant had no major effect on Th17 cell differentiation as the frequency of circulating Th17 cells was similar in carriers of the IL23R protective (A) and common (G) allele. Accordingly, Th17 cells generated from A and G donors produced similar amounts of Th17 cytokines. However, IL-23-mediated Th17 cell effector function was impaired, as Th17 cells from A allele carriers had significantly reduced IL-23-induced IL-17A production and STAT3 phosphorylation compared to G allele carriers. Our functional analysis of a human disease-associated gene variant demonstrates that IL23R R381Q exerts its protective effects through selective attenuation of IL-23-induced Th17 cell effector function without interfering with Th17 differentiation, and highlights its importance in the protection against IL-23-induced tissue pathologies.
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