Single-cell RNA sequencing reveals immune cell dysfunction in the peripheral blood of patients with highly aggressive gastric cancer.

Highly aggressive gastric cancer (HAGC) is a gastric cancer characterized by bone marrow metastasis and disseminated intravascular coagulation (DIC). Information about the disease is limited. Here we employed single-cell RNA sequencing to investigate peripheral blood mononuclear cells (PBMCs), aiming to unravel the immune response of patients toward HAGC. PBMCs from seven HAGC patients, six normal advanced gastric cancer (NAGC) patients, and five healthy individuals were analysed by single-cell RNA sequencing. The expression of genes of interest was validated by bulk RNA-sequencing and ELISA. We found a massive expansion of neutrophils in PBMCs of HAGC. These neutrophils are activated, but immature. Besides, mononuclear phagocytes exhibited an M2-like signature and T cells were suppressed and reduced in number. Analysis of cell-cell crosstalk revealed that several signalling pathways involved in neutrophil to T-cell suppression including APP-CD74, MIF-(CD74+CXCR2), and MIF-(CD74+CD44) pathways were increased in HAGC. NETosis-associated genes S100A8 and S100A9 as well as VEGF, PDGF, FGF, and NOTCH signalling that contribute to DIC development were upregulated in HAGC too. This study reveals significant changes in the distribution and interactions of the PBMC subsets and provides valuable insight into the immune response in patients with HAGC. S100A8 and S100A9 are highly expressed in HAGC neutrophils, suggesting their potential to be used as novel diagnostic and therapeutic targets for HAGC.

Single-Cell Analysis Reveals Cxcl14+ Fibroblast Accumulation in Regenerating Diabetic Wounds Treated by Hydrogel-Delivering Carbon Monoxide.

Nonhealing skin wounds are a problematic complication associated with diabetes. Therapeutic gases delivered by biomaterials have demonstrated powerful wound healing capabilities. However, the cellular responses and heterogeneity in the skin regeneration process after gas therapy remain elusive. Here, we display the benefit of the carbon monoxide (CO)-releasing hyaluronan hydrogel (CO@HAG) in promoting diabetic wound healing and investigate the cellular responses through single-cell transcriptomic analysis. The presented CO@HAG demonstrates wound microenvironment responsive gas releasing properties and accelerates the diabetic wound healing process in vivo. It is found that a new cluster of Cxcl14+ fibroblasts with progenitor property is accumulated in the CO@HAG-treated wound. This cluster of Cxcl14+ fibroblasts is yet unreported in the skin regeneration process. CO@HAG-treated wound macrophages feature a decrease in pro-inflammatory property, while their anti-inflammatory property increases. Moreover, the TGF-ß signal between the pro-inflammatory (M1) macrophage and the Cxcl14+ fibroblast in the CO@HAG-treated wound is attenuated based on cell-cell interaction analysis. Our study provides a useful hydrogel-mediated gas therapy method for diabetic wounds and new insights into cellular events in the skin regeneration process after gas-releasing biomaterials therapy.

Advances in the use of local anesthetic extended-release systems in pain management.

Pain management remains among the most common and largely unmet clinical problems today. Local anesthetics play an indispensable role in pain management. The main limitation of traditional local anesthetics is the limited duration of a single injection. To address this problem, catheters are often placed or combined with other drugs in clinical practice to increase the time that local anesthetics act. However, this method does not meet the needs of clinical analgesics. Therefore, many researchers have worked to develop local anesthetic extended-release types that can be administered in a single dose. In recent years, drug extended-release systems have emerged dramatically due to their long duration and efficacy, providing more possibilities for the application of local anesthetics. This paper summarizes the types of local anesthetic drug delivery systems and their clinical applications, discusses them in the context of relevant studies on local anesthetics, and provides a summary and outlook on the development of local anesthetic extended-release agents.

Restricting epigenetic activity promotes the reprogramming of transformed cells to pluripotency in a line-specific manner.

Somatic cell reprogramming and oncogenic transformation share surprisingly similar features, yet transformed cells are resistant to reprogramming. Epigenetic barriers must block transformed cells from reprogramming, but the nature of those barriers is unclear. In this study, we generated a systematic panel of transformed mouse embryonic fibroblasts (MEFs) using oncogenic transgenes and discovered transformed cell lines compatible with reprogramming when transfected with Oct4/Sox2/Klf4/Myc. By comparing the reprogramming-capable and incapable transformed lines we identified multiple stages of failure in the reprogramming process. Some transformed lines failed at an early stage, whilst other lines seemed to progress through a conventional reprogramming process. Finally, we show that MEK inhibition overcomes one critical reprogramming barrier by indirectly suppressing a hyperacetylated active epigenetic state. This study reveals that diverse epigenetic barriers underly resistance to reprogramming of transformed cells.

Disruption of neuronal RHEB signaling impairs oligodendrocyte differentiation and myelination through mTORC1-DLK1 axis.

How neuronal signaling affects brain myelination remains poorly understood. We show dysregulated neuronal RHEB-mTORC1-DLK1 axis impairs brain myelination. Neuronal Rheb cKO impairs oligodendrocyte differentiation/myelination, with activated neuronal expression of the imprinted gene Dlk1. Neuronal Dlk1 cKO ameliorates myelination deficit in neuronal Rheb cKO mice, indicating that activated neuronal Dlk1 expression contributes to impaired myelination caused by Rheb cKO. The effect of Rheb cKO on Dlk1 expression is mediated by mTORC1; neuronal mTor cKO and Raptor cKO and pharmacological inhibition of mTORC1 recapitulate elevated neuronal Dlk1 expression. We demonstrate that both a secreted form of DLK1 and a membrane-bound DLK1 inhibit the differentiation of cultured oligodendrocyte precursor cells into oligodendrocytes expressing myelin proteins. Finally, neuronal expression of Dlk1 in transgenic mice reduces the formation of mature oligodendrocytes and myelination. This study identifies Dlk1 as an inhibitor of oligodendrocyte myelination and a mechanism linking altered neuronal signaling with oligodendrocyte dysfunction.

Photoinhibiting via simultaneous photoabsorption and free-radical reaction for high-fidelity light-based bioprinting.

Light-based 3D bioprinting is now employed widely to fabricate geometrically complex constructs for various biomedical applications. However, the inherent light scattering defect creates significant challenges in patterning dilute hydrogels to form high-fidelity structures with fine-scale features. Herein, we introduce a photoinhibiting approach that can effectively suppress the light scattering effect via a mechanism of simultaneous photoabsorption and free-radical reaction. This biocompatible approach significantly improves the printing resolution (~1.2 - ~2.1 pixels depending on swelling) and shape fidelity (geometric error less than 5%), while minimising the costly trial-and-error procedures. The capability in patterning 3D complex constructs using different hydrogels is demonstrated by manufacturing various scaffolds featuring intricate multi-sized channels and thin-walled networks. Importantly, cellularised gyroid scaffolds (HepG2) are fabricated successfully, exhibiting high cell proliferation and functionality. The strategy established in this study promotes the printability and operability of light-based 3D bioprinting systems, allowing numerous new applications for tissue engineering.

Engineered human spinal cord-like tissues with dorsal and ventral neuronal progenitors for spinal cord injury repair in rats and monkeys.

Transplanting human neural progenitor cells is a promising method of replenishing the lost neurons after spinal cord injury (SCI), but differentiating neural progenitor cells into the diverse types of mature functional spinal cord neurons in vivo is challenging. In this study, engineered human embryonic spinal cord-like tissues with dorsal and ventral neuronal characters (DV-SC) were generated by inducing human neural progenitor cells (hscNPCs) to differentiate into various types of dorsal and ventral neuronal cells on collagen scaffold in vitro. Transplantation of DV-SC into complete SCI models in rats and monkeys showed better therapeutic effects than undifferentiated hscNPCs, including pronounced cell survival and maturation. DV-SC formed a targeted connection with the host's ascending and descending axons, partially restored interrupted neural circuits, and improved motor evoked potentials and the hindlimb function of animals with SCI. This suggests that the transplantation of pre-differentiated hscNPCs with spinal cord dorsal and ventral neuronal characteristics could be a promising strategy for SCI repair.

Antagonizing apolipoprotein J chaperone promotes proteasomal degradation of mTOR and relieves hepatic lipid deposition.

BACKGROUND AND AIMS: Overnutrition-induced activation of mammalian target of rapamycin (mTOR) dysregulates intracellular lipid metabolism and contributes to hepatic lipid deposition. Apolipoprotein J (ApoJ) is a molecular chaperone and participates in pathogen-induced and nutrient-induced lipid accumulation. This study investigates the mechanism of ApoJ-regulated ubiquitin-proteasomal degradation of mTOR, and a proof-of-concept ApoJ antagonist peptide is proposed to relieve hepatic steatosis. APPROACH AND RESULTS: By using omics approaches, upregulation of ApoJ was found in high-fat medium-fed hepatocytes and livers of patients with NAFLD. Hepatic ApoJ level associated with the levels of mTOR and protein markers of autophagy and correlated positively with lipid contents in the liver of mice. Functionally, nonsecreted intracellular ApoJ bound to mTOR kinase domain and prevented mTOR ubiquitination by interfering FBW7 ubiquitin ligase interaction through its R324 residue. In vitro and in vivo gain-of-function or loss-of-function analysis further demonstrated that targeting ApoJ promotes proteasomal degradation of mTOR, restores lipophagy and lysosomal activity, thus prevents hepatic lipid deposition. Moreover, an antagonist peptide with a dissociation constant (Kd) of 2.54 µM interacted with stress-induced ApoJ and improved hepatic pathology, serum lipid and glucose homeostasis, and insulin sensitivity in mice with NAFLD or type II diabetes mellitus. CONCLUSIONS: ApoJ antagonist peptide might be a potential therapeutic against lipid-associated metabolic disorders through restoring mTOR and FBW7 interaction and facilitating ubiquitin-proteasomal degradation of mTOR.

The homeodomain of Oct4 is a dimeric binder of methylated CpG elements.

Oct4 is essential to maintain pluripotency and has a pivotal role in establishing the germline. Its DNA-binding POU domain was recently found to bind motifs with methylated CpG elements normally associated with epigenetic silencing. However, the mode of binding and the consequences of this capability has remained unclear. Here, we show that Oct4 binds to a compact palindromic DNA element with a methylated CpG core (CpGpal) in alternative states of pluripotency and during cellular reprogramming towards induced pluripotent stem cells (iPSCs). During cellular reprogramming, typical Oct4 bound enhancers are uniformly demethylated, with the prominent exception of the CpGpal sites where DNA methylation is often maintained. We demonstrate that Oct4 cooperatively binds the CpGpal element as a homodimer, which contrasts with the ectoderm-expressed POU factor Brn2. Indeed, binding to CpGpal is Oct4-specific as other POU factors expressed in somatic cells avoid this element. Binding assays combined with structural analyses and molecular dynamic simulations show that dimeric Oct4-binding to CpGpal is driven by the POU-homeodomain whilst the POU-specific domain is detached from DNA. Collectively, we report that Oct4 exerts parts of its regulatory function in the context of methylated DNA through a DNA recognition mechanism that solely relies on its homeodomain.

Locally controlled release of immunosuppressive promotes survival of transplanted adult spinal cord tissue.

Transplantation of adult spinal cord tissue (aSCT) is a promising treatment for spinal cord injury (SCI) basing on various types of neural cells and matrix components inside aSCT. However, long-term systemic administration of immunosuppressors (e.g. tacrolimus, TAC) is required for the survival of allogeneic tissue, which often associated with severe side effects such as infection, liver damageand renal failure. In this study, a triglycerol monostearate (TGM)-based TAC delivery system (e.g. TAC@TGM) with high drug loading concentration was developed, which possessed injectable properties as well as sustainable and immune-responsive drug release behaviors. In complete transected SCI model, locally injected TAC@TGM could reduce the infiltration of inflammation cells, enhance the survival of transplanted aSCT (e.g. Tuj-1+ and NF+ neurons) and promote the recovery of locomotor function. Moreover, controlled release of TAC by TAC@TGM attenuated side effects of TAC on liver and kidneys compared with traditional systemic administration. More importantly, the developed TAC@TGM system provided a facile single dose of long-term immunosuppressive effect not just for aSCT transplantation, but also for other tissue/organ and cell transplantations.

Metabolic and epigenetic dysfunctions underlie the arrest of in vitro fertilized human embryos in a senescent-like state.

Around 60% of in vitro fertilized (IVF) human embryos irreversibly arrest before compaction between the 3- to 8-cell stage, posing a significant clinical problem. The mechanisms behind this arrest are unclear. Here, we show that the arrested embryos enter a senescent-like state, marked by cell cycle arrest, the down-regulation of ribosomes and histones and down-regulation of MYC and p53 activity. The arrested embryos can be divided into 3 types. Type I embryos fail to complete the maternal-zygotic transition, and Type II/III embryos have low levels of glycolysis and either high (Type II) or low (Type III) levels of oxidative phosphorylation. Treatment with the SIRT agonist resveratrol or nicotinamide riboside (NR) can partially rescue the arrested phenotype, which is accompanied by changes in metabolic activity. Overall, our data suggests metabolic and epigenetic dysfunctions underlie the arrest of human embryos.

Discovery of Novel 7-Azaindole Derivatives as Selective Covalent Fibroblast Growth Factor Receptor 4 Inhibitors for the Treatment of Hepatocellular Carcinoma.

Fibroblast growth factor receptor 4 (FGFR4) has been identified as a potential target for the treatment of hepatocellular carcinoma (HCC) with aberrant FGFR4 signaling because of its important role in HCC progression and development. Several FGFR4 inhibitors are under clinical development. Using a 7-azaindole scaffold, we discovered a series of novel selective and covalent FGFR4 inhibitors by performing a structure-based design approach. Representative compounds 24 and 30 exhibited potent FGFR4 inhibition and high selectivity among kinases. Western blot analysis showed that compounds 24 and 30 significantly inhibited the FGF19/FGFR4 signaling pathway in HuH-7 cells and effectively suppressed the proliferation of HuH-7 HCC cells and MDA-MB-453 breast cancer cells. Moreover, compound 30 exhibited significant in vivo antitumor activity in a mouse HuH-7 xenograft model. Thus, compound 30 and the 7-azaindole scaffold can be applied to develop anticancer agents for the treatment of cancers characterized by aberrant FGFR4 signaling.

Metal-organic framework-based hydrogel with structurally dynamic properties as a stimuli-responsive localized drug delivery system for cancer therapy.

Metal-organic framework (MOF) is an exciting class of porous biomaterials that have been considered as a carrier to store and deliver therapeutic drugs. However, similar to other nanomaterials, the application of MOF in clinical settings is still limited because of premature diffusion of their payloads and tissue off-targeting behavior. To overcome these challenges, we designed an MOF-based hydrogel with structurally dynamic properties, i.e., self-healing and shear-thinning, as an injectable localized drug delivery platform. The drug-encapsulating MOF hydrogel is formed through a dynamic coordination bond cross-linkage between a doxorubicin-loaded MOF (MOF@DOX) particle and a homemade bisphosphonate-modified hyaluronic acid (HA-BP) polymeric binder. The HA-BP·MOF@DOX hydrogel demonstrates pH- and ATP-responsive drug release characteristic and efficiently kills cancer cells in vitro. The animal experiments reveal that the HA-BP·MOF@DOX hydrogel has enhanced capability in terms of tumor growth suppression as compared to the MOF@DOX group, which can be attributed to drug localization in hydrogel superstructure and sustained release at the tumor site. The presented injectable dynamic MOF-based hydrogel is a promising in vivo localized drug delivery system for cancer treatment. Herein, we report the self-healing and shear-thinning of MOF-based drug carrier cross-linked by coordinate bonds for the first time and provide new insights and a facile chemical strategy for designing and fabricating MOF-based biomaterials by using bisphosphonate-zinc interaction. STATEMENT OF SIGNIFICANCE: Bisphosphonate-zinc interaction is a facile chemical strategy to cross-link metal-organic framework (MOF)-based hydrogel. The presented MOF-based hydrogel demonstrates structurally dynamic properties, including smooth injectability, self-healing, and shear-thinning. The developed MOF-based hydrogel possesses pH- and ATP-responsive drug release characteristic and kills cancer cells in vitro efficiently. The dynamic MOF-based hydrogel shows enhanced in vivo anticancer activity as compared to pure MOF particles. Self-healing and shear-thinning of metal-ligand cross-linked MOF-based drug delivery system are reported for the first time, thus providing new insights for the design and fabrication of MOF-based biomaterials.

In situ injectable hydrogel-loaded drugs induce anti-tumor immune responses in melanoma immunochemotherapy.

Melanoma is a highly aggressive tumor located in the skin, with limited traditional therapies. In order to reduce the side effects caused by traditional administration method and amplify the killing effect of immune system against tumor cells, an in situ injectable hydrogel drug delivery system is developed for the first time which co-delivers doxorubicin (Dox) and imiquimod (R837) for the synergistic therapy of melanoma. The mechanical properties and stability of the hydrogel are characterized and the optimal doses of hydrogel and drugs are also identified. As a result, the co-delivery system effectively suppresses melanoma growth and metastatic progression both in vitro and in vivo. Further studies show that the co-delivery system causes immunogenic cell death, activation of antigen presenting cells, comprising dendritic cells and M1 macrophages, and secretion of related cytokines consisted of tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), subsequently with the activation of T lymphocytes and natural killer cells in spleen and tumor area. The co-delivery system also decreases the suppressive immune responses, including infiltration of M2 macrophages and secretion of interleukin-10 (IL-10), in vivo. Besides, other death modes are induced by the co-delivery system, including apoptosis and non-apoptotic cell death. In a word, this co-delivery system induces melanoma cell death directly and activates immune system for further tumor killing simultaneously, which shows probability for precise targeted tumor therapy.

Flexible conductive silk-PPy hydrogel toward wearable electronic strain sensors.

Conductive hydrogels have been studied as promising materials for the flexible and wearable bioelectronics, because of their unique electrical and mechanical properties. Addition of conducting polymers in biomaterial-based hydrogel matrix is a simple yet effective way to construct hydrogels with good conductivity and flexibility. In this work, a conductive hydrogel composed by a silk hydrogel and a conducting polymer, polypyrrole (PPy), is developed via in-situ polymerization of pyrrole into the silk fibroin network. The silk-PPy hydrogel shows high conductivity (26 S/m), as well as sensitive and fast responses to corresponding conformation changes. Taking advantages of these properties, flexible and wearable strain sensors are proposed for the monitoring of various body movements, which can detect both the large and subtle human motions with good sensitivity, reproducibility and stability. The hybridization of biomaterials and conducting polymers endows the multifunctions of the conductive hydrogels, thus showing considerable potentials in the advancement of the wearable electronics.

Flexible conductive silk-PPy hydrogel toward wearable electronic strain sensors.

Conductive hydrogels have been studied as promising materials for the flexible and wearable bioelectronics, because of their unique electrical and mechanical properties. Addition of conducting polymers in biomaterial-based hydrogel matrix is a simple yet effective way to construct hydrogels with good conductivity and flexibility. In this work, a conductive hydrogel composed by a silk hydrogel and a conducting polymer, polypyrrole (PPy), is developed viain situpolymerization of pyrrole into the silk fibroin network. The silk-PPy hydrogel shows high conductivity (26 S m-1), as well as sensitive and fast responses to corresponding conformation changes. Taking advantages of these properties, flexible and wearable strain sensors are proposed for the monitoring of various body movements, which can detect both the large and subtle human motions with good sensitivity, reproducibility and stability. The hybridization of biomaterials and conducting polymers endows the multifunctions of the conductive hydrogels, thus showing considerable potentials in the advancement of the wearable electronics.

Bioinspired bimodal micro-nanofibrous scaffolds promote the tenogenic differentiation of tendon stem/progenitor cells for achilles tendon regeneration.

Poor tendon repair remains a clinical problem due to the difficulties in replicating the complex multiscale hierarchical structure of native tendons. In this work, a bioinspired fibrous scaffold with bimodal micro-nanofibers and a teno-inductive aligned topography was developed to replicate microscale collagen fibers and nanoscale collagen fibrils that compose native tendons. The results showed indicated that the combination of micro- and nanofibers enhanced the mechanical properties. Furthermore, their biological performance was assessed using tendon stem/progenitor cells (TSPCs). Micro-nanofibers induced a higher cell aspect ratio and enhanced the tenogenic differentiation of TSPCs compared to micro- and nanocontrols. Interestingly, it was observed that scaffold nanotopography and microstructures promoted tenogenesis via activating the TGF-ß/Smad2/3-mediated signaling pathway. The in situ implantation study confirmed that micro-nanofibrous scaffolds promoted the structural and mechanical properties of the regenerated Achilles tendon. Overall, our study shows that the bimodal micro-nanofibrous scaffold developed here presents a promising potential to improve the outcomes of tendon tissue engineering.

Assessment of ELISA-based method for the routine examination of serum indoxyl sulfate in patients with chronic kidney disease.

Introduction: Indoxyl sulfate (IS), a protein-bound uremic toxin, is associated with kidney function and chronic kidney disease (CKD)-related complications. Currently, serum IS levels are primarily quantified using mass spectrometry-based methods, which are not feasible for routine clinical examinations. Methods: The efficiencies of three commercial ELISA kits in determination of serum IS were validated by comparing with ultra-performance liquid chromatography (UPLC)-MS/MS-based method using Bland-Altman analysis. The associations between kidney parameters and serum IS levels determined by ELISA kit from Leadgene and UPLC-MS/MS were evaluated by Spearman correlation coefficient in a CKD validation cohort. Results: ELISA kit from Leadgene showed clinical agreement with UPLC-MS/MS in the determination of serum IS levels (p = 0.084). In patients with CKD, Spearman's correlation analysis revealed a perfect correlation between the IS levels determined using the Leadgene ELISA kit and UPLC-MS/MS (r = 0.964, p < 0.0001). IS levels determined using the Leadgene ELISA kit were associated with the estimated glomerular filtration rate (r = -0.772, p < 0.0001) and serum creatinine concentration (r = 0.824, p < 0.0001) in patients with CKD, and on dialysis (r = 0.557, p = 0.006). Conclusions: The Leadgene ELISA kit exhibits comparable efficacy to UPLC-MS/MS in quantifying serum IS levels, supporting that ELISA would be a personalized method for monitoring the dynamic changes in serum IS levels in dialysis patients to prevent the progression of CKD.

Synthesis and Evaluation of New Halogenated GR24 Analogs as Germination Promotors for Orobanche cumana.

Orobanche and Striga are parasitic weeds extremely well adapted to the life cycle of their host plants. They cannot be eliminated by conventional weed control methods. Suicidal germination induced by strigolactones (SLs) analogs is an option to control these weeds. Here, we reported two new halogenated (+)-GR24 analogs, named 7-bromo-GR24 (7BrGR24) and 7-fluoro-GR24 (7FGR24), which were synthesized using commercially available materials following simple steps. Both compounds strongly promoted seed germination of Orobanche cumana. Their EC50 values of 2.3±0.28×10-8M (7BrGR24) and 0.97±0.29×10-8M (7FGR24) were 3- and 5-fold lower, respectively, than those of (+)-GR24 and rac-GR24 (EC50=5.1±1.32-5.3±1.44×10-8; p<0.05). The 7FGR24 was the strongest seed germination promoter tested, with a stimulation percentage of 62.0±9.1% at 1.0×10-8M and 90.9±3.8% at 1.0×10-6M. It showed higher binding affinity (IC50=0.189±0.012µM) for the SL receptor ShHTL7 than (+)-GR24 (IC50=0.248±0.032µM), rac-GR24 (IC50=0.319±0.032µM), and 7BrGR24 (IC50=0.521±0.087µM). Molecular docking experiments indicated that the binding affinity of both halogenated analogs to the strigolactone receptor OsD14 was similar to that of (+)-GR24. Our results indicate that 7FGR24 is a promising agent for the control of parasitic weeds.

Transposable element sequence fragments incorporated into coding and noncoding transcripts modulate the transcriptome of human pluripotent stem cells.

Transposable elements (TEs) occupy nearly 40% of mammalian genomes and, whilst most are fragmentary and no longer capable of transposition, they can nevertheless contribute to cell function. TEs within genes transcribed by RNA polymerase II can be copied as parts of primary transcripts; however, their full contribution to mature transcript sequences remains unresolved. Here, using long and short read (LR and SR) RNA sequencing data, we show that 26% of coding and 65% of noncoding transcripts in human pluripotent stem cells (hPSCs) contain TE-derived sequences. Different TE families are incorporated into RNAs in unique patterns, with consequences to transcript structure and function. The presence of TE sequences within a transcript is correlated with TE-type specific changes in its subcellular distribution, alterations in steady-state levels and half-life, and differential association with RNA Binding Proteins (RBPs). We identify hPSC-specific incorporation of endogenous retroviruses (ERVs) and LINE:L1 into protein-coding mRNAs, which generate TE sequence-derived peptides. Finally, single cell RNA-seq reveals that hPSCs express ERV-containing transcripts, whilst differentiating subpopulations lack ERVs and express SINE and LINE-containing transcripts. Overall, our comprehensive analysis demonstrates that the incorporation of TE sequences into the RNAs of hPSCs is more widespread and has a greater impact than previously appreciated.