The proliferation and differentiation of spermatogonial stem cells in the frist wave of spermatogenesis in rats with Trib3 gene knockout.

This study explores the effects of Trib3 gene knockout on adult male rat spermatogenesis. Using CRISPR/Cas9, we knocked out the Trib3 gene in Wistar rats. Results indicate altered expression of PLZF, ID4, and c-KIT in knockout rats, suggesting impaired spermatogonial stem cell proliferation and differentiation. Histological analysis reveals reduced seminiferous tubule area and decreased spermatocyte numbers. Mating experiments demonstrate reduced offspring rates after the second self-mating in knockout rats. SYCP3, a meiosis marker, shows elevated expression in knockout rat testes at 14 days postpartum, suggesting an impact on reproductive processes. ELISA results indicate decreased testosterone, FSH, and FGF9 levels in knockout rat testicular tissues. In conclusion, Trib3 gene deletion may impede spermatogonial self-renewal and promote differentiation through the FSH-FGF9- c-KIT interaction and p38MAPK pathway, affecting reproductive capacity. These findings contribute to understanding the molecular mechanisms regulating spermatogenesis.

Metabolism and HSC fate: what NADPH is made for.

Mitochondrial metabolism plays a central role in the regulation of hematopoietic stem cell (HSC) biology. Mitochondrial fatty acid oxidation (FAO) is pivotal in controlling HSC self-renewal and differentiation. Herein, we discuss recent evidence suggesting that NADPH generated in the mitochondria can influence the fate of HSCs. Although NADPH has multiple functions, HSCs show high levels of NADPH that are preferentially used for cholesterol biosynthesis. Endogenous cholesterol supports the biogenesis of extracellular vesicles (EVs), which are essential for maintaining HSC properties. We also highlight the significance of EVs in hematopoiesis through autocrine signaling. Elucidating the mitochondrial NADPH-cholesterol axis as part of the metabolic requirements of healthy HSCs will facilitate the development of new therapies for hematological disorders.

CD44/PD-L1-mediated networks in drug resistance and immune evasion of breast cancer stem cells: Promising targets of natural compounds.

Cancer stem cells (CSCs) significantly interfere with immunotherapy, leading to challenges such as low response rates and acquired resistance. PD-L1 expression is associated with the CSC population's overexpression of CD44. Mounting evidence suggests that the breast cancer stem cell (BCSC) marker CD44 and the immune checkpoint PD-L1 contribute to treatment failure through their networks. Natural compounds can overcome therapy resistance in breast cancer by targeting mechanisms underlying resistance in BCSCs. This review provides an updated insight into the CD44 and PD-L1 networks of BCSCs in mediating metastasis and immune evasion. The review critically examines existing literature, providing a comprehensive understanding of the topic and emphasizing the impact of natural flavones on the signaling pathways of BCSCs. Additionally, the review discusses the potential of natural compounds in targeting CD44 and PD-L1 in breast cancer (BC). Natural compounds consistently show potential in targeting regulatory mechanisms of BCSCs, inducing loss of stemness, and promoting differentiation. They offer a promising approach for developing alternative therapeutic strategies to manage breast cancer.

A novel chemical genetic approach reveals paralog-specific role of ERK1/2 in mouse embryonic stem cell fate control.

Introduction: Mouse embryonic stem cell (ESC) self-renewal can be maintained through dual inhibition of GSK3 and MEK kinases. MEK has two highly homologous downstream kinases, extracellular signal-regulated kinase 1 and 2 (ERK1/2). However, the exact roles of ERK1/2 in mouse ESC self-renewal and differentiation remain unclear. Methods: We selectively deleted or inhibited ERK1, ERK2, or both using genetic and chemical genetic approaches combined with small molecule inhibitors. The effects of ERK paralog-specific inhibition on mouse ESC self-renewal and differentiation were then assessed. Results: ERK1/2 were found to be dispensable for mouse ESC survival and self-renewal. The inhibition of both ERK paralogs, in conjunction with GSK3 inhibition, was sufficient to maintain mouse ESC self-renewal. In contrast, selective deletion or inhibition of only one ERK paralog did not mimic the effect of MEK inhibition in promoting mouse ESC self-renewal. Regarding ESC differentiation, inhibition of ERK1/2 prevented mesendoderm differentiation. Additionally, selective inhibition of ERK1, but not ERK2, promoted mesendoderm differentiation. Discussion: These findings suggest that ERK1 and ERK2 have both overlapping and distinct roles in regulating ESC self-renewal and differentiation. This study provides new insights into the molecular mechanisms of ERK1/2 in governing ESC maintenance and lineage commitment, potentially informing future strategies for controlling stem cell fate in research and therapeutic applications.

Stimulating effect of nanocurcumin and crocin on proliferation and pluripotency of bone marrow-derived mesenchymal stem cells.

Objectives: Enhancement of proliferation, pluripotency, and self-renewal capacity as the unique features of MSCs can improve their therapeutic potential to regenerate tissues. In this context, crocin and curcumin, carotenoid compounds with outstanding medicinal properties, could be promising for cell protection and growth. This study aimed to evaluate the impact of nanocurcumin and crocin on BM-MSCs proliferation and pluripotency in vitro. Materials and Methods: BM-MSC were isolated from the iliac crest of SCI patients who were candidates for stem cell therapy. The effect of crocin and nanocurcumin on MSC proliferation was evaluated using MTT and PDT assay. The percentage of apoptotic MSCs was measured by flow cytometry. Furthermore, mRNA and protein expression of OCT4 and SOX2 as the proliferation and self-renewal related genes were quantified by real-time PCR and western blotting, respectively. Results: Our findings demonstrated that only low concentrations of nanocurcumin (0.3 and 0.7 µM) and crocin (2.5 5 µM) significantly affected MSCs proliferation and protected them from apoptosis. Also, crocin and nanocurcumin at low doses caused an elevation in the mRNA and protein expression levels of OCT4 and SOX2 genes. In contrast, high concentrations decreased the survival of MSCs and led to increased apoptosis compared with the untreated group. Conclusion: Our results suggest that using nanocurcumin and crocin separately in culturing MSCs can be considered proliferative agents to prepare the more advantageous tool for cell therapies. However, more in vitro and preclinical research is needed in this area.

Unraveling the role of long non-coding RNAs in therapeutic resistance in acute myeloid leukemia: New prospects & challenges.

Acute Myeloid Leukemia (AML) is a fatal hematological disease characterized by the unchecked proliferation of immature myeloid blasts in different tissues developed by various mutations in hematopoiesis. Despite intense chemotherapeutic regimens, patients often experience poor outcomes, leading to substandard remission rates. In recent years, long non-coding RNAs (lncRNAs) have increasingly become important prognostic and therapeutic hotspots, due to their contributions to dysregulating many functional epigenetic, transcriptional, and post-translational mechanisms leading to alterations in cell expressions, resulting in increased chemoresistance and reduced apoptosis in leukemic cells. Through this review, I highlight and discuss the latest advances in understanding the major mechanisms through which lncRNAs confer therapy resistance in AML. In addition, I also provide perspective on the current strategies to target lncRNA expressions. A better knowledge of the critical role that lncRNAs play in controlling treatment outcomes in AML will help improve existing medications and devise new ones.

Slow-replicating leukemia cells represent a leukemia stem cell population with high cell-surface CD74 expression.

Persistence of quiescent leukemia stem cells (LSCs) after treatment most likely contributes to chemotherapy resistance and poor prognosis of leukemia patients. Identification of this quiescent cell population would facilitate eradicating LSCs. Here, using a cell-tracing PKH26 (PKH) dye that can be equally distributed to daughter cells following cell division in vivo, we identify a label-retaining slow-cycling leukemia cell population from AML1-ETO9a (AE9a) leukemic mice. We find that, compared with cells not maintaining PKH-staining, a higher proportion of PKH-retaining cells are in G0 phase, and PKH-retaining cells exhibit increased colony formation ability and leukemia initiation potential. In addition, PKH-retaining cells possess high chemo-resistance and are more likely to be localized to the endosteal bone marrow region. Based on the transcriptional signature, HLA class II histocompatibility antigen gamma chain (Cd74) is highly expressed in PKH-retaining leukemia cells. Furthermore, cell surface CD74 was identified to be highly expressed in LSCs of AE9a mice and CD34+ human leukemia cells. Compared to Lin-CD74- leukemia cells, Lin-CD74+ leukemia cells of AE9a mice exhibit higher stemness properties. Collectively, our findings reveal that the identified slow-cycling leukemia cell population represents an LSC population, and CD74+ leukemia cells possess stemness properties, suggesting that CD74 is a candidate LSC surface marker.

Synergistic effect and molecular mechanism of nicotinamide and UM171 in ex vivo expansion of long-term hematopoietic stem cells.

Introduction: Several approaches to expand human hematopoietic stem cells (HSCs) have been reported, but the ability of these methods to expand long-term hematopoietic stem cells (LT-HSCs) remains to be improved, which limits the application of HSCs-based therapies. Methods: CD34+ cells were purified from umbilical cord blood using MacsCD34 beads, and then cultured for 12 d in a serum-free medium. Flow cytometry was used to detect phenotype, cell cycle distribution, and apoptosis of the cultured cells. Colony-forming cell (CFC) assays can evaluate multi-lineage differentiation potential of HSCs. Real-time polymerase chain reaction was employed to detect the expression of genes related to self-renewal programs and antioxidant activity. DCFH-DA probes were used to evaluate intracellular production of reactive oxygen species (ROS). Determination of the effect of different culture conditions on the balance of cytokine by cytometric bead array. Results: Here, we show a combination, Nicotinamide (NAM) combined with pyrimidoindole derivative UM171, can massively expand LT-HSCs ex vivo, and the expanded cells maintained the capability of self-renewal and multilineage differentiation. Additionally, our data indicated that UM171 promoted self-renewal of HSCs by inducing HSCs entry into the cell cycle and activating Notch and Wnt pathways, but the infinite occurrence of this process may lead to mitochondrial metabolism disorder and differentiation of HSCs. NAM kept HSCs in their primitive and dormant states by reducing intracellular ROS levels and upregulating the expression of stemness related genes, so we believed that NAM can act as a brake to control the above process. Conclusions: The discovery of the synergistic effect of NAM and UM171 for expanding LT-HSCs provides a new strategy in solving the clinical issue of limited numbers of HSCs.

A dual-color PAX7 and MYF5 in vivo reporter to investigate muscle stem cell heterogeneity in regeneration and aging.

Increasing evidence suggests that the muscle stem cell (MuSC) pool is heterogeneous. In particular, a rare subset of PAX7-positive MuSCs that has never expressed the myogenic regulatory factor MYF5 displays unique self-renewal and engraftment characteristics. However, the scarcity and limited availability of protein markers make the characterization of these cells challenging. Here, we describe the generation of StemRep reporter mice enabling the monitoring of PAX7 and MYF5 proteins based on equimolar levels of dual nuclear fluorescence. High levels of PAX7 protein and low levels of MYF5 delineate a deeply quiescent MuSC subpopulation with an increased capacity for asymmetric division and distinct dynamics of activation, proliferation, and commitment. Aging primarily reduces the MYF5Low MuSCs and skews the stem cell pool toward MYF5High cells with lower quiescence and self-renewal potential. Altogether, we establish the StemRep model as a versatile tool to study MuSC heterogeneity and broaden our understanding of mechanisms regulating MuSC quiescence and self-renewal in homeostatic, regenerating, and aged muscles.

p21/Zbtb18 repress the expression of cKit to regulate the self-renewal of hematopoietic stem cells.

The maintenance of hematopoietic stem cells (HSCs) is a complex process involving numerous cell-extrinsic and -intrinsic regulators. The first member of the cyclin-dependent kinase family of inhibitors to be identified, p21, has been reported to perform a wide range of critical biological functions, including cell cycle regulation, transcription, differentiation, and so on. Given the previous inconsistent results regarding the functions of p21 in HSCs in a p21-knockout mouse model, we employed p21-tdTomato (tdT) mice to further elucidate its role in HSCs during homeostasis. The results showed that p21-tdT+ HSCs exhibited increased self-renewal capacity compared to p21-tdT- HSCs. Zbtb18, a transcriptional repressor, was upregulated in p21-tdT+ HSCs, and its knockdown significantly impaired the reconstitution capability of HSCs. Furthermore, p21 interacted with ZBTB18 to co-repress the expression of cKit in HSCs and thus regulated the self-renewal of HSCs. Our data provide novel insights into the physiological role and mechanisms of p21 in HSCs during homeostasis independent of its conventional role as a cell cycle inhibitor.

Ohwia caudata aqueous extract attenuates senescence in aging adipose-derived mesenchymal stem cells.

Stem cells exhibit pluripotency and self-renewal abilities. Adipose-derived mesenchymal stem cells can potentially be used to reconstruct various tissues. They possess significant versatility and alleviate various aging-related diseases. Unfortunately, aging leads to senescence, apoptosis, and a decline in regenerative capacity in adipose-derived mesenchymal stem cells. These changes necessitate a strategy to mitigate the effects of aging on stem cells. Ohwia caudata (O. caudata) has therapeutic effects against several illnesses. However, studies on whether O. caudata has therapeutic effects against aging are lacking. In this study, we aimed to identify potential therapeutic anti-aging effects in the crude aqueous extract of O. caudata on adipose-derived mesenchymal stem cells. Using 0.1 µM doxorubicin, we induced aging in human adipose-derived mesenchymal stem cells (hADMSCs) and evaluated whether various concentrations of O. caudata aqueous extract exhibit anti-aging effects on them. The O. caudata extract exhibited significant antioxidant effects on hADMSCs without any toxicity. Furthermore, after treatment with the O. caudata aqueous extract, the levels of mitochondrial superoxide, DNA double-strand breaks, and telomere shortening were reduced in the hADMSCs subjected to doxorubicin-induced aging. The extract also suppressed doxorubicin-induced aging by upregulating klotho and downregulating p21 in hADMSCs. These findings indicated that the O. caudata extract exhibited anti-aging properties that modulated hADMSC homeostasis. Therefore, it could be a potential candidate for restoring the self-renewal ability and multipotency of aging hADMSCs.

Hallmarks of cancer stemness.

Cancer stemness is recognized as a key component of tumor development. Previously coined "cancer stem cells" (CSCs) and believed to be a rare population with rigid hierarchical organization, there is good evidence to suggest that these cells exhibit a plastic cellular state influenced by dynamic CSC-niche interplay. This revelation underscores the need to reevaluate the hallmarks of cancer stemness. Herein, we summarize the techniques used to identify and characterize the state of these cells and discuss their defining and emerging hallmarks, along with their enabling and associated features. We also highlight potential future directions in this field of research.

Chromatin modifier Hmga2 promotes adult hematopoietic stem cell function and blood regeneration in stress conditions.

The molecular mechanisms governing the response of hematopoietic stem cells (HSCs) to stress insults remain poorly defined. Here, we investigated effects of conditional knock-out or overexpression of Hmga2 (High mobility group AT-hook 2), a transcriptional activator of stem cell genes in fetal HSCs. While Hmga2 overexpression did not affect adult hematopoiesis under homeostasis, it accelerated HSC expansion in response to injection with 5-fluorouracil (5-FU) or in vitro treatment with TNF-α. In contrast, HSC and megakaryocyte progenitor cell numbers were decreased in Hmga2 KO animals. Transcription of inflammatory genes was repressed in Hmga2-overexpressing mice injected with 5-FU, and Hmga2 bound to distinct regions and chromatin accessibility was decreased in HSCs upon stress. Mechanistically, we found that casein kinase 2 (CK2) phosphorylates the Hmga2 acidic domain, promoting its access and binding to chromatin, transcription of anti-inflammatory target genes, and the expansion of HSCs under stress conditions. Notably, the identified stress-regulated Hmga2 gene signature is activated in hematopoietic stem progenitor cells of human myelodysplastic syndrome patients. In sum, these results reveal a TNF-α/CK2/phospho-Hmga2 axis controlling adult stress hematopoiesis.

Cardiac differentiation is modulated by anti-apoptotic signals in murine embryonic stem cells.

BACKGROUND: Embryonic stem cells (ESCs) serve as a crucial ex vivo model, representing epiblast cells derived from the inner cell mass of blastocyst-stage embryos. ESCs exhibit a unique combination of self-renewal potency, unlimited proliferation, and pluripotency. The latter is evident by the ability of the isolated cells to differentiate spontaneously into multiple cell lineages, representing the three primary embryonic germ layers. Multiple regulatory networks guide ESCs, directing their self-renewal and lineage-specific differentiation. Apoptosis, or programmed cell death, emerges as a key event involved in sculpting and forming various organs and structures ensuring proper embryonic development. However, the molecular mechanisms underlying the dynamic interplay between differentiation and apoptosis remain poorly understood. AIM: To investigate the regulatory impact of apoptosis on the early differentiation of ESCs into cardiac cells, using mouse ESC (mESC) models - mESC-B-cell lymphoma 2 (BCL-2), mESC-PIM-2, and mESC-metallothionein-1 (MET-1) - which overexpress the anti-apoptotic genes Bcl-2, Pim-2, and Met-1, respectively. METHODS: mESC-T2 (wild-type), mESC-BCL-2, mESC-PIM-2, and mESC-MET-1 have been used to assess the effect of potentiated apoptotic signals on cardiac differentiation. The hanging drop method was adopted to generate embryoid bodies (EBs) and induce terminal differentiation of mESCs. The size of the generated EBs was measured in each condition compared to the wild type. At the functional level, the percentage of cardiac differentiation was measured by calculating the number of beating cardiomyocytes in the manipulated mESCs compared to the control. At the molecular level, quantitative reverse transcription-polymerase chain reaction was used to assess the mRNA expression of three cardiac markers: Troponin T, GATA4, and NKX2.5. Additionally, troponin T protein expression was evaluated through immunofluorescence and western blot assays. RESULTS: Our findings showed that the upregulation of Bcl-2, Pim-2, and Met-1 genes led to a reduction in the size of the EBs derived from the manipulated mESCs, in comparison with their wild-type counterpart. Additionally, a decrease in the count of beating cardiomyocytes among differentiated cells was observed. Furthermore, the mRNA expression of three cardiac markers - troponin T, GATA4, and NKX2.5 - was diminished in mESCs overexpressing the three anti-apoptotic genes compared to the control cell line. Moreover, the overexpression of the anti-apoptotic genes resulted in a reduction in troponin T protein expression. CONCLUSION: Our findings revealed that the upregulation of Bcl-2, Pim-2, and Met-1 genes altered cardiac differentiation, providing insight into the intricate interplay between apoptosis and ESC fate determination.

Stem cell dynamics and cellular heterogeneity across lineage subtypes of castrate-resistant prostate cancer.

To resist lineage-dependent therapies such as androgen receptor inhibition, prostate luminal epithelial adenocarcinoma cells often adopt a stem-like state resulting in lineage plasticity and phenotypic heterogeneity. Castrate-resistant prostate adenocarcinoma can transition to neuroendocrine (NE) and occasionally to amphicrine, co-expressed luminal and NE, phenotypes. We developed castrate-resistant prostate cancer (CRPC) patient-derived organoid models that preserve heterogeneity of the originating tumor, including an amphicrine model displaying a range of luminal and NE phenotypes. To gain biological insight and to identify potential treatment targets within heterogeneous tumor cell populations, we assessed the lineage hierarchy and molecular characteristics of various CRPC tumor subpopulations. Transcriptionally similar stem/progenitor (St/Pr) cells were identified for all lineage populations. Lineage tracing in amphicrine CRPC showed that heterogeneity originated from distinct subclones of infrequent St/Pr cells that produced mainly quiescent differentiated amphicrine progeny. By contrast, adenocarcinoma CRPC progeny originated from St/Pr cells and self-renewing differentiated luminal cells. Neuroendocrine prostate cancer (NEPC) was composed almost exclusively of self-renewing St/Pr cells. Amphicrine subpopulations were enriched for secretory luminal, mesenchymal, and enzalutamide treatment persistent signatures that characterize clinical progression. Finally, the amphicrine St/Pr subpopulation was specifically depleted with an AURKA inhibitor, which blocked tumor growth. These data illuminate distinct stem cell (SC) characteristics for subtype-specific CRPC in addition to demonstrating a context for targeting differentiation-competent prostate SCs.

Tbl1 promotes Wnt-ß-catenin signaling-induced degradation of the Tcf7l1 protein in mouse embryonic stem cells.

Activation of the Wnt-ß-catenin signaling pathway by CHIR99021, a specific inhibitor of GSK3ß, induces Tcf7l1 protein degradation, which facilitates the maintenance of an undifferentiated state in mouse embryonic stem cells (mESCs); however, the precise mechanism is still unclear. Here, we showed that the overexpression of transducin-ß-like protein 1 (Tbl1, also known as Tbl1x) or its family member Tblr1 (also known as Tbl1xr1) can decrease Tcf7l1 protein levels, whereas knockdown of each gene increases Tcf7l1 levels without affecting Tcf7l1 transcription. Interestingly, only Tbl1, and not Tblr1, interacts with Tcf7l1. Mechanistically, Tbl1 translocates from the cytoplasm into the nucleus in association with ß-catenin (CTNNB1) after the addition of CHIR99021 and functions as an adaptor to promote ubiquitylation of the Tcf7l1 protein. Functional assays further revealed that enforced expression of Tbl1 is capable of delaying mESC differentiation. In contrast, knockdown of Tbl1 attenuates the effect of CHIR99021 on Tcf7l1 protein stability and mESC self-renewal. Our results provide insight into the regulatory network of the Wnt-ß-catenin signaling pathway involved in promoting the maintenance of naïve pluripotency.

A germline point mutation in the MYC-FBW7 phosphodegron initiates hematopoietic malignancies.

Oncogenic activation of MYC in cancers predominantly involves increased transcription rather than coding region mutations. However, MYC-dependent lymphomas frequently acquire point mutations in the MYC phosphodegron, including at threonine 58 (T58), where phosphorylation permits binding via the FBW7 ubiquitin ligase triggering MYC degradation. To understand how T58 phosphorylation functions in normal cell physiology, we introduced an alanine mutation at T58 (T58A) into the endogenous c-Myc locus in the mouse germline. While MYC-T58A mice develop normally, lymphomas and myeloid leukemias emerge in ∼60% of adult homozygous T58A mice. We found that primitive hematopoietic progenitor cells from MYC-T58A mice exhibit aberrant self-renewal normally associated with hematopoietic stem cells (HSCs) and up-regulate a subset of MYC target genes important in maintaining stem/progenitor cell balance. In lymphocytes, genomic occupancy by MYC-T58A was increased at all promoters compared with WT MYC, while genes differentially expressed in a T58A-dependent manner were significantly more proximal to MYC-bound enhancers. MYC-T58A lymphocyte progenitors exhibited metabolic alterations and decreased activation of inflammatory and apoptotic pathways. Our data demonstrate that a single point mutation stabilizing MYC is sufficient to skew target gene expression, producing a profound gain of function in multipotential hematopoietic progenitors associated with self-renewal and initiation of lymphomas and leukemias.

The satellite cell in skeletal muscle: A story of heterogeneity.

Skeletal muscle is a highly represented tissue in mammals and is composed of fibers that are extremely adaptable and capable of regeneration. This characteristic of muscle fibers is made possible by a cell type called satellite cells. Adjacent to the fibers, satellite cells are found in a quiescent state and located between the muscle fibers membrane and the basal lamina. These cells are required for the growth and regeneration of skeletal muscle through myogenesis. This process is known to be tightly sequenced from the activation to the differentiation/fusion of myofibers. However, for the past fifteen years, researchers have been interested in examining satellite cell heterogeneity and have identified different subpopulations displaying distinct characteristics based on localization, quiescence state, stemness capacity, cell-cycle progression or gene expression. A small subset of satellite cells appears to represent multipotent long-term self-renewing muscle stem cells (MuSC). All these distinctions led us to the hypothesis that the characteristics of myogenesis might not be linear and therefore may be more permissive based on the evidence that satellite cells are a heterogeneous population. In this review, we discuss the different subpopulations that exist within the satellite cell pool to highlight the heterogeneity and to gain further understanding of the myogenesis progress. Finally, we discuss the long term self-renewing MuSC subpopulation that is capable of dividing asymmetrically and discuss the molecular mechanisms regulating MuSC polarization during health and disease.

Asparagine Synthetase Marks a Distinct Dependency Threshold for Cardiomyocyte Dedifferentiation.

BACKGROUND: Adult mammalian cardiomyocytes have limited proliferative capacity, but in specifically induced contexts they traverse through cell-cycle reentry, offering the potential for heart regeneration. Endogenous cardiomyocyte proliferation is preceded by cardiomyocyte dedifferentiation (CMDD), wherein adult cardiomyocytes revert to a less matured state that is distinct from the classical myocardial fetal stress gene response associated with heart failure. However, very little is known about CMDD as a defined cardiomyocyte cell state in transition. METHODS: Here, we leveraged 2 models of in vitro cultured adult mouse cardiomyocytes and in vivo adeno-associated virus serotype 9 cardiomyocyte-targeted delivery of reprogramming factors (Oct4, Sox2, Klf4, and Myc) in adult mice to study CMDD. We profiled their transcriptomes using RNA sequencing, in combination with multiple published data sets, with the aim of identifying a common denominator for tracking CMDD. RESULTS: RNA sequencing and integrated analysis identified Asparagine Synthetase (Asns) as a unique molecular marker gene well correlated with CMDD, required for increased asparagine and also for distinct fluxes in other amino acids. Although Asns overexpression in Oct4, Sox2, Klf4, and Myc cardiomyocytes augmented hallmarks of CMDD, Asns deficiency led to defective regeneration in the neonatal mouse myocardial infarction model, increased cell death of cultured adult cardiomyocytes, and reduced cell cycle in Oct4, Sox2, Klf4, and Myc cardiomyocytes, at least in part through disrupting the mammalian target of rapamycin complex 1 pathway. CONCLUSIONS: We discovered a novel gene Asns as both a molecular marker and an essential mediator, marking a distinct threshold that appears in common for at least 4 models of CMDD, and revealing an Asns/mammalian target of rapamycin complex 1 axis dependency for dedifferentiating cardiomyocytes. Further study will be needed to extrapolate and assess its relevance to other cell state transitions as well as in heart regeneration.

Potential targets and therapeutics for cancer stem cell-based therapy against drug resistance in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the most common digestive malignancyin the world, which is frequently diagnosed at late stage with a poor prognosis. For most patients with advanced HCC, the therapeutic options arelimiteddue to cancer occurrence of drug resistance. Hepatic cancer stem cells (CSCs) account for a small subset of tumor cells with the ability of self-renewal and differentiationin HCC. It is widely recognized that the presence of CSCs contributes to primary and acquired drug resistance. Therefore, hepatic CSCs-targeted therapy is considered as a promising strategy to overcome drug resistance and improve therapeutic outcome in HCC. In this article, we review drug resistance in HCC and provide a summary of potential targets for CSCs-based therapy. In addition, the development of CSCs-targeted therapeuticsagainst drug resistance in HCC is summarized in both preclinical and clinical trials. The in-depth understanding of CSCs-related drug resistance in HCC will favor optimization of the current therapeutic strategies and gain encouraging therapeutic outcomes.