Vitamin C facilitates pluripotent stem cell maintenance by promoting pluripotency gene transcription

Ascorbic acid and its transporter SVCT2, affect radial glia cells differentiation in postnatal stages

Radial glia (RG) cells generate neurons and glial cells that make up the cerebral cortex. Both in rodents and humans, these stem cells remain for a specific time after birth, named late radial glia (lRG). The knowledge of lRG and molecules that may be involved in their differentiation is based on very limited data. We analyzed whether ascorbic acid (AA) and its transporter SVCT2, are involved in lRG cells differentiation. We demonstrated that lRG cells are highly present between the first and fourth postnatal days. Anatomical characterization of lRG cells, revealed that lRG cells maintained their bipolar morphology and stem-like character. When lRG cells were labeled with adenovirus-eGFP at 1 postnatal day, we detected that some cells display an obvious migratory neuronal phenotype, suggesting that lRG cells continue generating neurons postnatally. Moreover, we demonstrated that SVCT2 was apically polarized in lRG cells. In vitro studies using the transgenic mice SVCT2+/- and SVCT2tg (SVCT2-overexpressing mouse), showed that decreased SVCT2 levels led to accelerated differentiation into astrocytes, whereas both AA treatment and elevated SVCT2 expression maintain the lRG cells in an undifferentiated state. In vivo overexpression of SVCT2 in lRG cells generated cells with a rounded morphology that were migratory and positive for proliferation and neuronal markers. We also examined mediators that can be involved in AA/SVCT2-modulated signaling pathways, determining that GSK3-β through AKT, mTORC2, and PDK1 is active in brains with high levels of SVCT2/AA. Our data provide new insights into the role of AA and SVCT2 in late RG cells.

Avian iPSC Derivation to Recover Threatened Wild Species: A Comprehensive Review in Light of Well-Established Protocols

Induced pluripotent stem cells (iPSCs) were first generated by Yamanaka in 2006, revolutionizing research by overcoming limitations imposed by the use of embryonic stem cells. In terms of the conservation of endangered species, iPSC technology presents itself as a viable alternative for the manipulation of target genetics without compromising specimens. Although iPSCs have been successfully generated for various species, their application in nonmammalian species, particularly avian species, requires further in-depth investigation to cover the diversity of wild species at risk and their different protocol requirements. This study aims to provide an overview of the workflow for iPSC induction, comparing well-established protocols in humans and mice with the limited information available for avian species. Here, we discuss the somatic cell sources to be reprogrammed, genetic factors, delivery methods, enhancers, a brief history of achievements in avian iPSC derivation, the main approaches for iPSC characterization, and the future perspectives and challenges for the field. By examining the current protocols and state-of-the-art techniques employed in iPSC generation, we seek to contribute to the development of efficient and species-specific iPSC methodologies for at-risk avian species. The advancement of iPSC technology holds great promise for achieving in vitro germline competency and, consequently, addressing reproductive challenges in endangered species, providing valuable tools for basic research, bird genetic preservation and rescue, and the establishment of cryobanks for future conservation efforts.

Role of vitamin C and SVCT2 in neurogenesis

Different studies have established the fundamental role of vitamin C in proliferation, differentiation, and neurogenesis in embryonic and adult brains, as well as in in vitro cell models. To fulfill these functions, the cells of the nervous system regulate the expression and sorting of sodium-dependent vitamin C transporter 2 (SVCT2), as well as the recycling of vitamin C between ascorbic acid (AA) and dehydroascorbic acid (DHA) via a bystander effect. SVCT2 is a transporter preferentially expressed in neurons and in neural precursor cells. In developmental stages, it is concentrated in the apical region of the radial glia, and in adult life, it is expressed preferentially in motor neurons of the cerebral cortex, starting on postnatal day 1. In neurogenic niches, SVCT2 is preferentially expressed in precursors with intermediate proliferation, where a scorbutic condition reduces neuronal differentiation. Vitamin C is a potent epigenetic regulator in stem cells; thus, it can induce the demethylation of DNA and histone H3K27m3 in the promoter region of genes involved in neurogenesis and differentiation, an effect mediated by Tet1 and Jmjd3 demethylases, respectively. In parallel, it has been shown that vitamin C induces the expression of stem cell-specific microRNA, including the Dlk1-Dio3 imprinting region and miR-143, which promotes stem cell self-renewal and suppresses de novo expression of the methyltransferase gene Dnmt3a. The epigenetic action of vitamin C has also been evaluated during gene reprogramming of human fibroblasts to induced pluripotent cells, where it has been shown that vitamin C substantially improves the efficiency and quality of reprogrammed cells. Thus, for a proper effect of vitamin C on neurogenesis and differentiation, its function as an enzymatic cofactor, modulator of gene expression and antioxidant is essential, as is proper recycling from DHA to AA by various supporting cells in the CNS.

miR-361 and miR-34a suppress foot-and-mouth disease virus proliferation by activating immune response signaling in PK-15 cells

Foot-and-mouth disease (FMD) severely impacts cloven-hoofed live-stock production, leading to serious economic losses and international restriction on the trade of animals and animal products worldwide. MiRNAs serve key roles in viral immunity and regulation. However, the knowledge about miRNAs regulation in FMDV infection is still limited. In this study, we found that FMDV infection caused rapid cytopathic in PK-15 cell. To investigate the miRNAs' function in FMDV infection, we performed knockdown of endogenous Dgcr8 using its specific siRNA and found that interference of Dgcr8 inhibited cellular miRNA expression and increased FMDV production, including viral capsid proteins expression, viral genome copies and virus titer, suggesting that miRNAs play an important role in FMDV infection. To obtain a full perspective on miRNA expression profiling after FMDV infection, we performed miRNA sequencing and found that FMDV infection caused inhibition of miRNA expression in PK-15 cells. Together with the target prediction result, miR-34a and miR-361 were screened for further study. Function study showed that no matter plasmid or mimics-mediated overexpression of miR-34a and miR-361 both suppressed FMDV replication, while inhibition of endogenous miR-34a and miR-361 expression using specific inhibitors significantly increased FMDV replication. Further study showed that miR-34a and miR-361 stimulated IFN-β promoter activity and activated interferon-stimulated response element (ISRE). In addition, ELISA test found that miR-361 and miR-34a increased secretion level of IFN-β and IFN-γ, which may contribute to repression of FMDV replication. This study preliminary revealed that miR-361 and miR-34a inhibited FMDV proliferation via stimulating immune response.

Ascorbic Acid/Retinol and/or Inflammatory Stimuli's Effect on Proliferation/Differentiation Properties and Transcriptomics of Gingival Stem/Progenitor Cells

The present study explored the effects of ascorbic-acid (AA)/retinol and timed inflammation on the stemness, the regenerative potential, and the transcriptomics profile of gingival mesenchymal stem/progenitor cells' (G-MSCs). STRO-1 (mesenchymal stem cell marker) immuno-magnetically sorted G-MSCs were cultured in basic medium (control group), in basic medium with IL-1β (1 ng/mL), TNF-α (10 ng/mL) and IFN-γ (100 ng/mL, inflammatory-medium), in basic medium with AA (250 µmol/L) and retinol (20 µmol/L) (AA/retinol group) or in inflammatory medium with AA/retinol (inflammatory/AA/retinol group; n = 5/group). The intracellular levels of phosphorylated and total β-Catenin at 1 h, the expression of stemness genes over 7 days, the number of colony-forming units (CFUs) as well as the cellular proliferation aptitude over 14 days, and the G-MSCs' multilineage differentiation potential were assessed. Next-generation sequencing was undertaken to elaborate on up-/downregulated genes and altered intracellular pathways. G-MSCs demonstrated all mesenchymal stem/progenitor cells characteristics. Controlled inflammation with AA/retinol significantly elevated NANOG (p < 0.05). The AA/retinol-mediated reduction in intracellular phosphorylated β-Catenin was restored through the effect of controlled inflammation (p < 0.05). Cellular proliferation was highest in the AA/retinol group (p < 0.05). AA/retinol counteracted the inflammation-mediated reduction in G-MSCs' clonogenic ability and CFUs. Amplified chondrogenic differentiation was observed in the inflammatory/AA/retinol group. At 1 and 3 days, the differentially expressed genes were associated with development, proliferation, and migration (FOS, EGR1, SGK1, CXCL5, SIPA1L2, TFPI2, KRATP1-5), survival (EGR1, SGK1, TMEM132A), differentiation and mineral absorption (FOS, EGR1, MT1E, KRTAP1-5, ASNS, PSAT1), inflammation and MHC-II antigen processing (PER1, CTSS, CD74) and intracellular pathway activation (FKBP5, ZNF404). Less as well as more genes were activated the longer the G-MSCs remained in the inflammatory medium or AA/retinol, respectively. Combined, current results point at possibly interesting interactions between controlled inflammation or AA/retinol affecting stemness, proliferation, and differentiation attributes of G-MSCs.

SVCT2 Overexpression and Ascorbic Acid Uptake Increase Cortical Neuron Differentiation, Which Is Dependent on Vitamin C Recycling between Neurons and Astrocytes

During brain development, sodium–vitamin C transporter (SVCT2) has been detected primarily in radial glial cells in situ, with low-to-absent expression in cerebral cortex neuroblasts. However, strong SVCT2 expression is observed during the first postnatal days, resulting in increased intracellular concentration of vitamin C. Hippocampal neurons isolated from SVCT2 knockout mice showed shorter neurites and low clustering of glutamate receptors. Other studies have shown that vitamin C-deprived guinea pigs have reduced spatial memory, suggesting that ascorbic acid (AA) and SVCT2 have important roles in postnatal neuronal differentiation and neurite formation. In this study, SVCT2 lentiviral overexpression induced branching and increased synaptic proteins expression in primary cultures of cortical neurons. Analysis in neuroblastoma 2a (Neuro2a) and human subventricular tumor C3 (HSVT-C3) cells showed similar branching results. SVCT2 was mainly observed in the cell membrane and endoplasmic reticulum; however, it was not detected in the mitochondria. Cellular branching in neuronal cells and in a previously standardized neurosphere assay is dependent on the recycling of vitamin C or reduction in dehydroascorbic acid (DHA, produced by neurons) by glial cells. The effect of WZB117, a selective glucose/DHA transporter 1 (GLUT1) inhibitor expressed in glial cells, was also studied. By inhibiting GLUT1 glial cells, a loss of branching is observed in vitro, which is reproduced in the cerebral cortex in situ. We concluded that vitamin C recycling between neurons and astrocyte-like cells is fundamental to maintain neuronal differentiation in vitro and in vivo. The recycling activity begins at the cerebral postnatal cortex when neurons increase SVCT2 expression and concomitantly, GLUT1 is expressed in glial cells.

The Impact of Vitamin C on Different System Models of Werner Syndrome

Significance: Werner syndrome (WS) is a rare autosomal recessive malady typified by a pro-oxidant/proinflammatory status, genetic instability, and by the early onset of numerous age-associated illnesses. The protein malfunctioning in WS individuals (WRN) is a helicase/exonuclease implicated in transcription, DNA replication/repair, and telomere maintenance. Recent Advances: In the last two decades, a series of important biological systems were created to comprehend at the molecular level the effect of a defective WRN protein. Such biological tools include mouse and worm (Caenorhabditis elegans) with a mutation in the Wrn helicase ortholog as well as human WS-induced pluripotent stem cells that can ultimately be differentiated into most cell lineages. Such WS models have identified anomalies related to the hallmarks of aging. Most importantly, vitamin C counteracts these age-related cellular phenotypes in these systems. Critical Issues: Vitamin C is the only antioxidant agent capable of reversing the cellular aging-related phenotypes in those biological systems. Since vitamin C is a cofactor for many hydroxylases and mono- or dioxygenase, it adds another level of complexity in deciphering the exact molecular pathways affected by this vitamin. Moreover, it is still unclear whether a short- or long-term vitamin C supplementation in human WS patients who already display aging-related phenotypes will have a beneficial impact. Future Directions: The discovery of new molecular markers specific to the modified biological pathways in WS that can be used for novel imaging techniques or as blood markers will be necessary to assess the favorable effect of vitamin C supplementation in WS. Antioxid. Redox Signal. 34, 856-874.

FOXC1 Downregulates Nanog Expression by Recruiting HDAC2 to Its Promoter in F9 Cells Treated by Retinoic Acid

FOXC1, a transcription factor involved in cell differentiation and embryogenesis, is demonstrated to be a negative regulator of Nanog in this study. FOXC1 is up-regulated in retinoic acid-induced differentiation of F9 Embryonal Carcinoma (EC) cells; furthermore, FOXC1 specifically inhibits the core pluripotency factor Nanog by binding to the proximal promoter. Overexpression of FOXC1 in F9 or knockdown in 3T3 results in the down-regulation or up-regulation of Nanog mRNA and proteins, respectively. In order to explain the mechanism by which FOXC1 inhibits Nanog expression, we identified the co-repressor HDAC2 from the FOXC1 interactome. FOXC1 recruits HDAC2 to Nanog promoter to decrease H3K27ac enrichment, resulting in transcription inhibition of Nanog. To the best of our knowledge, this is the first report that FOXC1 is involved in the epigenetic regulation of gene expression.

Induction of Stem Cell Like Cells from Mouse Embryonic Fibroblast by Short-Term Shear Stress and Vitamin C

Induced pluripotent stem cells (iPSCs) are a good medicine source because of their potential to differentiate into various tissues or cells. However, traditionally, iPSCs made by specific transgenes and virus vectors are not appropriate for clinical use because of safety concerns and risk of tumor development. The goal of this research was to develop an alternative method for reprogramming, using small molecules and external stimuli. Two groups were established: short-term shear stress (STSS) under suspension culture and a combination of short-term shear stress and vitamin C (SSVC) under suspension culture. For STSS, the pipetting was carried out for cells twice per day for 2 min for 14 days in the embryonic stem cell (ES) medium. In the case of SSVC, the procedure was the same as for STSS however, its ES medium included 10 µM of vitamin C. After 14 days, all spheroids were picked and checked for pluripotency by ALP (alkaline phosphatase) assay and immunocytochemistry. Both groups partially showed the characteristics of stem cells but data demonstrated that the spheroids under shear stress and vitamin C had improved stem cell-like properties. This research showed the possibility of external stimuli and small molecules to reprogram the somatic cells without the use of transgenes.

New insights into Vitamin C function: Vitamin C induces JAK2 activation through its receptor-like transporter SVCT2

Vitamin C (VitC) is a requisite nutrient for humans and other primates. Extensive research continuously illustrates the applications of VitC in promoting cell reprogramming, fine-tuning embryonic stem cell function, and fighting diseases. Given its chemical reduction property, VitC predominantly acts as an antioxidant to reduce reactive oxygen species (ROS) and as a cofactor for certain dioxygenases involved in epigenetic regulation. Here, we propose that VitC is also a bio-signaling molecule based on the finding that sodium-dependent VitC transporter (SVCT) 2 is a novel receptor-like transporter of VitC that possesses dual activities in mediating VitC uptake and Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 2 signaling pathway. Through interaction, SVCT2 induces JAK2 phosphorylation while transporting VitC into cells. Activated JAK2 phosphorylates the C-terminus of SVCT2, resulting in the recruitment and activation of STAT2. As a highlight, our results suggest that the activation of JAK2 synergistically promotes regulation of VitC in ROS scavenging and epigenetic modifications through phosphorylating pyruvate dehydrogenase kinase 1, ten-eleven translocation enzyme 3, and histone H3 Tyr⁴¹. Furthermore, VitC-activated JAK2 exhibits bidirectional effects in regulating cell pluripotency and differentiation. Our results thus reveal that the SVCT2-mediated JAK2 activation facilitates VitC functions in a previously unknown manner.

Positive feedback between retinoic acid and 2-phospho-L-ascorbic acid trisodium salt during somatic cell reprogramming

Retinoic acid (RA) and 2-phospho-L-ascorbic acid trisodium salt (AscPNa) promote the reprogramming of mouse embryonic fibroblasts to induced pluripotent stem cells. In the current studies, the lower abilities of RA and AscPNa to promote reprogramming in the presence of each other suggested that they may share downstream pathways at least partially. The hypothesis was further supported by the RNA-seq analysis which demonstrated a high-level overlap between RA-activated and AscPNa activated genes during reprogramming. In addition, RA upregulated Glut1/3, facilitated the membrane transportation of dehydroascorbic acid, the oxidized form of L-ascorbic acid, and subsequently maintained intracellular L-ascorbic acid at higher level and for longer time. On the other hand, AscPNa facilitated the mesenchymal-epithelial transition during reprogramming, downregulated key mesenchymal transcriptional factors like Zeb1 and Twist1, subsequently suppressed the expression of Cyp26a1/b1 which mediates the metabolism of RA, and sustained the intracellular level of RA. Furthermore, the different abilities of RA and AscPNa to induce mesenchymal-epithelial transition, pluripotency, and neuronal differentiation explain their complex contribution to reprogramming when used individually or in combination. Therefore, the current studies identified a positive feedback between RA and AscPNa, or possibility between vitamin A and C, and further explored their contributions to reprogramming.

Vitamin C: A stem cell promoter in cancer metastasis and immunotherapy

Vitamin C is an electron donor and is involved in a variety of biochemical reactions in stem cell and cancer stem cell, as well as collagen synthesis and the regulation of hypoxia-inducible factor synthesis, which two affect extracellular matrix remodelling and hence cancer metastasis. Specific doses of vitamin C can stop cancer cell glycolysis and block nitroso synthesis, indicating the potential of vitamin C in cancer treatment. Recent studies preliminary revealed Vitamin C enhance the cancer's immune response to anti PD-L1 therapy through multiple indirect approaches. Herein we reviewed the recent function of vitamin C for further research in sequential aspects of cancer stem cell, extracellular matrix remodeling, cancer metastasis and cancer immunotherapy.

Ascorbic Acid, Inflammatory Cytokines (IL-1β/TNF-α/IFN-γ), or Their Combination's Effect on Stemness, Proliferation, and Differentiation of Gingival Mesenchymal Stem/Progenitor Cells

Objective

Ascorbic acid (AA) and controlled inflammatory stimuli are postulated to possess the ability to independently exert positive effects on a variety of proliferative, pluripotency, and differentiation attributes of gingival mesenchymal stem/progenitor cells (G-MSCs). The current study's objective was to explore and compare for the first time the impact of the major inflammatory cytokines (IL-1β/TNF-α/IFN-γ), AA, or their combination on multipotency/pluripotency, proliferative, and differentiation characteristics of G-MSCs.

Design

Human G-MSCs (n = 5) were isolated and cultured in basic medium (control group), in basic medium with major inflammatory cytokines; 1 ng/ml IL-1β, 10 ng/ml TNF-α, and 100 ng/ml IFN-γ (inflammatory group), in basic medium with 250 μmol/l AA (AA group) and in inflammatory medium supplemented by AA (inflammatory/AA group). All media were renewed three times per week. In stimulated G-MSCs intracellular β-catenin at 1 hour, pluripotency gene expression at 1, 3, and 5 days, as well as colony-forming units (CFUs) ability and cellular proliferation over 14 days were examined. Following a five-days stimulation in the designated groups, multilineage differentiation was assessed via qualitative and quantitative histochemistry as well as mRNA expression.

Results

β-Catenin significantly decreased intracellularly in all experimental groups (p = 0.002, Friedman). AA group exhibited significantly higher cellular counts on days 3, 6, 7, and 13 (p < 0.05) and the highest CFUs at 14 days [median-CFUs (Q25/Q75); 40 (15/50), p = 0.043]. Significantly higher Nanog expression was noted in AA group [median gene-copies/PGK1 (Q25/Q75); 0.0006 (0.0002/0.0007), p < 0.01, Wilcoxon-signed-rank]. Significant multilineage differentiation abilities, especially into osteogenic and chondrogenic directions, were further evident in the AA group.

Conclusions

AA stimulation enhances G-MSCs' stemness, proliferation, and differentiation properties, effects which are associated with a Wnt/β-catenin signaling pathway activation. Apart from initially boosting cellular metabolism as well as Sox2 and Oct4A pluripotency marker expression, inflammation appeared to attenuate these AA-induced positive effects. Current results reveal that for AA to exert its beneficial effects on G-MSCs' cellular attributes, it requires to act in an inflammation-free microenvironment.

Vitamin C improves the therapeutic potential of human amniotic epithelial cells in premature ovarian insufficiency disease

BACKGROUND

Human amniotic epithelial cell (hAEC) transplantation holds great promise in treating premature ovarian insufficiency (POI). However, some deficient biological characteristics of hAECs restrict their application.

METHODS

Vitamin C (VC) was added to the culture media of hAECs for 2 weeks. Then, the proliferative ability, migration ability, pluripotency, and self-renewal of VC-treated hAECs (VC-hAECs) were determined. Next, hAECs and VC-hAECs were transplanted into the ovaries of cyclophosphamide (CTX)-induced POI model mice. The ovarian function of POI mice was evaluated after transplantation by counting follicle numbers and measuring the blood levels of AMH, E2, and FSH. The rescue effects of VC-hAECs and hAECs were unveiled by coculturing with CTX-damaged human ovarian granulosa cells (hGCs) and analyzing relative marker expression. Additionally, ovarian marker expression and transplant survival were detected in POI mice after transplantation to verify the beneficial effect of VC-hAECs. The cytokine profiles of VC-hAECs and hAECs were revealed by performing a cytokine array and an ELISA to show their paracrine function.

RESULTS

Our results indicated that VC promoted the proliferation, migration, pluripotency, and self-renewal of hAECs in vitro. The most effective concentration of VC was 50 μg/ml. After transplantation into the POI mouse model, VC-hAECs reversed ovarian function more powerfully than hAECs. Human granulosa cell marker expression in CTX-damaged hGCs was increased after coculture with VC-hAECs compared with hAECs. In the ovaries of the POI mice, ovarian marker expression was greater after VC-hAEC transplantation than after hAEC transplantation. VC-hAECs showed higher transplant survival than hAECs. Furthermore, VC-hAECs secreted more growth factors than hAECs.

CONCLUSION

Treatment with VC promoted the proliferation, migration, self-renewal, and paracrine functions of hAECs. Additionally, VC elevated the therapeutic potential of hAECs in treating POI.

Supporting Cell-Based Tendon Therapy: Effect of PDGF-BB and Ascorbic Acid on Rabbit Achilles Tenocytes in Vitro

Cell-based tendon therapies with tenocytes as a cell source need effective tenocyte in vitro expansion before application for tendinopathies and tendon injuries. Supplementation of tenocyte culture with biomolecules that can boost proliferation and matrix synthesis is one viable option for supporting cell expansion. In this in vitro study, the impacts of ascorbic acid or PDGF-BB supplementation on rabbit Achilles tenocyte culture were studied. Namely, cell proliferation, changes in gene expression of several ECM and tendon markers (collagen I, collagen III, fibronectin, aggrecan, biglycan, decorin, ki67, tenascin-C, tenomodulin, Mohawk, α-SMA, MMP-2, MMP-9, TIMP1, and TIMP2) and ECM deposition (collagen I and fibronectin) were assessed. Ascorbic acid and PDGF-BB enhanced tenocyte proliferation, while ascorbic acid significantly accelerated the deposition of collagen I. Both biomolecules led to different changes in the gene expression profile of the cultured tenocytes, where upregulation of collagen I, Mohawk, decorin, MMP-2, and TIMP-2 was observed with ascorbic acid, while these markers were downregulated by PDGF-BB supplementation. Vice versa, there was an upregulation of fibronectin, biglycan and tenascin-C by PDGF-BB supplementation, while ascorbic acid led to a downregulation of these markers. However, both biomolecules are promising candidates for improving and accelerating the in vitro expansion of tenocytes, which is vital for various tendon tissue engineering approaches or cell-based tendon therapy.

Metabolic-Epigenetic Axis in Pluripotent State Transitions

Cell state transition (CST) occurs during embryo development and in adult life in response to different stimuli and is associated with extensive epigenetic remodeling. Beyond growth factors and signaling pathways, increasing evidence point to a crucial role of metabolic signals in this process. Indeed, since several epigenetic enzymes are sensitive to availability of specific metabolites, fluctuations in their levels may induce the epigenetic changes associated with CST. Here we analyze how fluctuations in metabolites availability influence DNA/chromatin modifications associated with pluripotent stem cell (PSC) transitions. We discuss current studies and focus on the effects of metabolites in the context of naïve to primed transition, PSC differentiation and reprogramming of somatic cells to induced pluripotent stem cells (iPSCs), analyzing their mechanism of action and the causal correlation between metabolites availability and epigenetic alteration.

Human iPSC-derived MSCs (iMSCs) from aged individuals acquire a rejuvenation signature

BACKGROUND

Primary mesenchymal stem cells (MSCs) are fraught with aging-related shortfalls. Human-induced pluripotent stem cell (iPSC)-derived MSCs (iMSCs) have been shown to be a useful clinically relevant source of MSCs that circumvent these aging-associated drawbacks. To date, the extent of the retention of aging-hallmarks in iMSCs differentiated from iPSCs derived from elderly donors remains unclear.

METHODS

Fetal femur-derived MSCs (fMSCs) and adult bone marrow MSCs (aMSCs) were isolated, corresponding iPSCs were generated, and iMSCs were differentiated from fMSC-iPSCs, from aMSC-iPSCs, and from human embryonic stem cells (ESCs) H1. In addition, typical MSC characterization such as cell surface marker expression, differentiation capacity, secretome profile, and trancriptome analysis were conducted for the three distinct iMSC preparations-fMSC-iMSCs, aMSC-iMSCs, and ESC-iMSCs. To verify these results, previously published data sets were used, and also, additional aMSCs and iMSCs were analyzed.

RESULTS

fMSCs and aMSCs both express the typical MSC cell surface markers and can be differentiated into osteogenic, adipogenic, and chondrogenic lineages in vitro. However, the transcriptome analysis revealed overlapping and distinct gene expression patterns and showed that fMSCs express more genes in common with ESCs than with aMSCs. fMSC-iMSCs, aMSC-iMSCs, and ESC-iMSCs met the criteria set out for MSCs. Dendrogram analyses confirmed that the transcriptomes of all iMSCs clustered together with the parental MSCs and separated from the MSC-iPSCs and ESCs. iMSCs irrespective of donor age and cell type acquired a rejuvenation-associated gene signature, specifically, the expression of INHBE, DNMT3B, POU5F1P1, CDKN1C, and GCNT2 which are also expressed in pluripotent stem cells (iPSCs and ESC) but not in the parental aMSCs. iMSCs expressed more genes in common with fMSCs than with aMSCs. Independent real-time PCR comparing aMSCs, fMSCs, and iMSCs confirmed the differential expression of the rejuvenation (COX7A, EZA2, and TMEM119) and aging (CXADR and IGSF3) signatures. Importantly, in terms of regenerative medicine, iMSCs acquired a secretome (e.g., angiogenin, DKK-1, IL-8, PDGF-AA, osteopontin, SERPINE1, and VEGF) similar to that of fMSCs and aMSCs, thus highlighting their ability to act via paracrine signaling.

CONCLUSIONS

iMSCs irrespective of donor age and cell source acquire a rejuvenation gene signature. The iMSC concept could allow circumventing the drawbacks associated with the use of adult MSCs und thus provide a promising tool for use in various clinical settings in the future.

Foot-and-mouth disease virus infection stimulates innate immune signaling in the mouse macrophage RAW 264.7 cells

The innate immune system acts as the first line of defense against invasion by bacterial and viral pathogens. The role of macrophages in innate immune responses to foot-and-mouth disease virus (FMDV) is poorly understood. To determine the mechanism underlying activation of innate immunity after FMDV infection in macrophages, we performed FMDV infection in mouse macrophage RAW 264.7 cells and found that FMDV serotype O infection induced a cytopathic effect. We then evaluated the gene expression profile in macrophage RAW 264.7 cells after FMDV infection using systematic microarray analysis. Gene ontology annotation and enrichment analysis revealed that FMDV promoted expression in a group of genes that are enriched in innate immune response and inflammatory response processes. Further research demonstrated that FMDV serotype O infection enhanced NF-κB, Toll-like, and RIG-I-like receptor signaling pathways and proteins expression and increased transcription and expression of a series of cytokines and interferons, as proved by qRT-PCR, Western blot, ELISA, and dual-luciferase reporter assay. Our study concluded that FMDV infection triggers the innate immune response in macrophages after activation of multiple innate immune pathway receptors and proteins by FMDV serotype O, resulting in activation and secretion of a series of cytokines and interferons.

Ascorbic acid promotes cardiomyogenesis through SMAD1 signaling in differentiating mouse embryonic stem cells

Numerous groups have documented that Ascorbic Acid (AA) promotes cardiomyocyte differentiation from both mouse and human ESCs and iPSCs. AA is now considered indispensable for the routine production of hPSC-cardiomyocytes (CMs) using defined media; however, the mechanisms involved with the inductive process are poorly understood. Using a genetically modified mouse embryonic stem cell (mESC) line containing a dsRED transgene driven by the cardiac-restricted portion of the ncx1 promoter, we show that AA promoted differentiation of mESCs to CMs in a dose- and time-dependent manner. Treatment of mPSCs with AA did not modulate total SMAD content; however, the phosphorylated/active forms of SMAD2 and SMAD1/5/8 were significantly elevated. Co-administration of the SMAD2/3 activator Activin A with AA had no significant effect, but the addition of the nodal co-receptor TDGF1 (Cripto) antagonized AA’s cardiomyogenic-promoting ability. AA could also reverse some of the inhibitory effects on cardiomyogenesis of ALK/SMAD2 inhibition by SB431542, a TGFβ pathway inhibitor. Treatment with BMP2 and AA strongly amplified the positive cardiomyogenic effects of SMAD1/5/8 in a dose-dependent manner. AA could not, however, rescue dorsomorphin-mediated inhibition of ALK/SMAD1 activity. Using an inducible model system, we found that SMAD1, but not SMAD2, was essential for AA to promote the formation of TNNT2⁺-CMs. These data firmly demonstrate that BMP receptor-activated SMADs, preferential to TGFβ receptor-activated SMADs, are necessary to promote AA stimulated cardiomyogenesis. AA-enhanced cardiomyogenesis thus relies on the ability of AA to modulate the ratio of SMAD signaling among the TGFβ-superfamily receptor signaling pathways.

Vitamin C in Stem Cell Biology: Impact on Extracellular Matrix Homeostasis and Epigenetics

Transcription factors and signaling molecules are well-known regulators of stem cell identity and behavior; however, increasing evidence indicates that environmental cues contribute to this complex network of stimuli, acting as crucial determinants of stem cell fate. l-Ascorbic acid (vitamin C (VitC)) has gained growing interest for its multiple functions and mechanisms of action, contributing to the homeostasis of normal tissues and organs as well as to tissue regeneration. Here, we review the main functions of VitC and its effects on stem cells, focusing on its activity as cofactor of Fe⁺²/αKG dioxygenases, which regulate the epigenetic signatures, the redox status, and the extracellular matrix (ECM) composition, depending on the enzymes' subcellular localization. Acting as cofactor of collagen prolyl hydroxylases in the endoplasmic reticulum, VitC regulates ECM/collagen homeostasis and plays a key role in the differentiation of mesenchymal stem cells towards osteoblasts, chondrocytes, and tendons. In the nucleus, VitC enhances the activity of DNA and histone demethylases, improving somatic cell reprogramming and pushing embryonic stem cell towards the naive pluripotent state. The broad spectrum of actions of VitC highlights its relevance for stem cell biology in both physiology and disease.

Metabolic Reprogramming of Stem Cell Epigenetics

For many years, stem cell metabolism was viewed as a byproduct of cell fate status rather than an active regulatory mechanism; however, there is now a growing appreciation that metabolic pathways influence epigenetic changes associated with lineage commitment, specification, and self-renewal. Here we review how metabolites generated during glycolytic and oxidative processes are utilized in enzymatic reactions leading to epigenetic modifications and transcriptional regulation. We discuss how "metabolic reprogramming" contributes to global epigenetic changes in the context of naive and primed pluripotent states, somatic reprogramming, and hematopoietic and skeletal muscle tissue stem cells, and we discuss the implications for regenerative medicine.

Analyses of basal media and serum for in vitro expansion of suspension peripheral blood mononucleated stem cell

Transplantation of stem cells requires a huge amount of cells, deeming the expansion of the cells in vitro necessary. The aim of this study is to define the optimal combination of basal medium and serum for the expansion of suspension peripheral blood mononucleated stem cells (PBMNSCs) without resulting in loss in the differentiation potential. Mononucleated cells were isolated from both mice and human peripheral blood samples through gradient centrifugation and expanded in α-MEM, RPMI, MEM or DMEM supplemented with either NBCS or FBS. The suspension cells were then differentiated to osteoblast. Our data suggested that α-MEM supplemented with 10 % (v/v) NBCS gives the highest fold increase after 14 days of culture for both mice and human PBMNSCs, which were ~1.51 and ~2.01 times, respectively. The suspension PBMNSCs in the respective medium were also able to maintain osteoblast differentiation potential as supported by the significant increase in ALP specific activity. The cells are also viable during the differentiated states when using this media. All these data strongly suggested that α-MEM supplemented with 10 % NBCS is the best media for the expansion of both mouse and human suspension PBMNSCs.

Generation of induced pluripotent stem cells from renal tubular cells of a patient with Alport syndrome

Alport syndrome (AS) is a hereditary disease that leads to kidney failure and is caused by mutations in the COL4A3, COL4A4, and COL4A5 genes that lead to the absence of collagen α3α4α5 (IV) networks in the mature kidney glomerular basement membrane. Approximately 80% of AS is X-linked because of mutations in COL4A5, the gene encoding the alpha 5 chain of type IV collagen. To investigate the pathogenesis of AS at the genetic level, we generated induced pluripotent stem cells (iPSCs) from renal tubular cells of a patient with AS. The successful iPSC generation laid the foundation to master the repair of the COL4A5 gene and to evaluate the differentiation of iPSC into Sertoli cells and the accompanying epigenetic changes at each stage. The generation of iPSCs from AS patients not only confirms that iPSCs could be generated from renal tubular cells, but also provides a novel type of genetic therapy for AS patients. In this study, we generated iPSCs from renal tubular cells via ectopic expression of four transcription factors (Oct4, Sox2, c-myc, and Klf4). According to the human embryonic stem cell (hESC) charter, iPSC formation was confirmed by comparatively analyzing hESC markers via colony morphology, immunohistochemistry, qRT-PCR, flow cytometry, gene expression profiling of the three germ layers, and karyotyping. Our results demonstrated that iPSCs were similar to hESCs with regard to morphology, proliferation, hESC-specific surface marker expression, and differentiation into the cell types of the three germ layers. The efficient generation of iPSCs from the renal tubular cells of an AS patient would provide a novel model to investigate the mechanisms underlying AS and to develop new treatments for AS.

Stress signaling in mammalian oocytes and embryos: a basis for intervention and improvement of outcomes

Oocytes and early stage embryos are highly sensitive to variation in diverse exogenous factors such as temperature, osmolarity, oxygen, nutrient restriction, pH, shear stress, toxins, amino acid availability, and lipids. It is becoming increasingly apparent that many such factors negatively affect the endoplasmic reticulum, protein synthesis and protein processing, initiating ER stress and unfolded protein responses. As a result, ER stress signaling serves as a common mediator of cellular responses to diverse stressors. In oocytes and embryos, this leads to developmental arrest and epigenetic changes. Recent studies have revealed that preventing ER stress or inhibiting ER stress signaling can preserve or even enhance oocyte and embryo developmental potential. This review examines ER stress signaling, how it arises, how it affects oocytes and embryos, and how its occurrence can be managed or prevented.

Fibronectin regulation by vitamin C treatment in kidneys of nicotinic mice offspring

Background:

Maternal cigarette smoking causes health risks and developmental defects in the offspring. So far, many studies have been conducted to suppress the effects of nicotine. However, the effects of coadministration of vitamin C and nicotine on extracellular matrix have not gained enough attention.

Objectives:

This study decided to investigate the effects of vitamin C on fibronectin expression in kidneys of mice offspring, treated with nicotine.

Materials and Methods:

Eighteen female pregnant BALB/c mice were selected; six mice in the experimental group 1 (exp 1) received nicotine (3 mg/kg/day), six mice in the experimental group 2 (exp 2) received 3 mg/kg/day nicotine and 9 mg/kg/day vitamin C simultaneously, and six were used as the control group and received 3 mL/kg/day normal saline via intraperitoneal (IP) injection parallel to other groups, since the 6th day of gestation to the end of prenatal period. In the first days of delivery, fibronectin content of neonatal kidneys was studied by immunohistochemistry (IHC) assay and gene expression was studied by the real-time PCR.

Results:

IHC results showed that fibronectin reaction significantly increased in proximal convoluted tubules of exp 1 compared with the control offspring; on the other hand, fibronectin reaction decreased in the mice offspring of exp 2. Gene expression results showed that fibronectin expression in the exp 1 offspring significantly increased compared with the control ones and fibronectin expression decreased in the mice offspring of exp 2.

Conclusions:

This study revealed that vitamin C could reduce the fibronectin accumulation effects of nicotine on kidney.

Vitamin C supplementation enhances compact morulae formation but reduces the hatching blastocyst rate of bovine somatic cell nuclear transfer embryos

Vitamin C, an antioxidant that reduces reactive oxygen species (ROS) in cells, is capable of significantly improving the developmental competence of porcine and mouse somatic cell nuclear transfer (SCNT) embryos, both in vitro and in vivo. In the present study, the effects of vitamin C on the developmental competence of bovine SCNT embryos were investigated. The results indicated that vitamin C (40 μg/mL) positively affected the scavenging of intracellular ROS, cleavage rate at 24 h (76.67 vs. 68.26%, p<0.05), compact morulae formation (60.83 vs. 51.30%, p<0.05), and the blastomere apoptosis index (3.70 ± 1.41 vs. 4.43% ± 1.65, p<0.05) of bovine SCNT embryos. However, vitamin C supplementation did not significantly affect the blastocyst formation rate and proportion of inner cell mass over total cells per blastocyst on day 7. Moreover, vitamin C supplementation obviously impaired the total cell numbers per blastocyst (97.20 ± 11.35 vs. 88.57 ± 10.43, p<0.05) on day 7 and the hatching blastocysts formation rate on day 9 (26.51 vs. 50.65%, p<0.05) compared with that of the untreated group. Vitamin C supplementation preferentially improved the viability of bovine SCNT embryos prior to the blastocyst stage, but did not enhance the formation and quality of blastocysts in vitro. In conclusion, the effect of vitamin C on the development of bovine SCNT embryos is complex, and vitamin C is not a suitable antioxidant chemical for the in vitro culture of bovine SCNT embryos.

Continuous passages accelerate the reprogramming of mouse induced pluripotent stem cells

Induced pluripotent stem cells (iPSCs) are usually generated by reprogramming somatic cells through transduction with a transcription factor cocktail. However, the low efficiency of this procedure has kept iPSCs away from the study of the clinical application of stem cell biology. Our research shows that continuous passage increases the efficiency of reprogramming. Compared with conventional method of establishment of iPSCs, more embryonic stem cell (ESC)-like clones are generated by continuous passage during early reprogramming. These inchoate clones, indistinguishable from genuine ESC clones, are closer to fully reprogrammed cells compared with those derived from classical iPSC induction, which increased the expression of pluripotent gene markers and the levels of demethylation of Oct4 and Nanog. These results suggested that full reprogramming is a gradual process that does not merely end at the point of the activation of endogenous pluripotency-associated genes. Continuous passage could increase the pluripotency of induced cells and accelerate the process of reprogramming by epigenetic modification. In brief, we have provided an advanced strategy to accelerate the reprogramming and generate more nearly fully reprogrammed iPSCs efficiently and rapidly.