Biology subjects

Lei, A.

Publications and source records attributed to Lei, A..

11 recordsLinked to original sources

bioRxiv2024

In vivo engineered quadrivalent CAR-macrophages break tumor barrier,remodel TME and overcome tumor heterogeneity through antigen spreading

CAR-macrophages have shown promising prospect in treating solid tumors. Ex vivo engineered CAR-macrophages face the challenge of low transfection efficiency, long preparation cycle, and limited cell number. Here, we designed two novel CAR molecules, GPC3-CAR-Super IL-2 and FAP-CAR-{bigtriangleup}TGF{beta}RII from the perspective of targeting tumor cells and improving tumor microenvironment, and generated quadrivalent CAR-macrophages in vivo for treating solid tumors by the LNP-mRNA system. We found that in vivo engineered quadrivalent CAR-macrophages can strongly activate tumor immunity and achieve complete tumor regression without significant side effects. Mechanically, in vivo engineered quadrivalent CAR-macrophages broke down physical barriers around the tumor constructed by CAFs and significantly promoted infiltration and expansion of CD8+ T cells. Moreover, the transiently formed CAR-macrophages in vivo are sufficient to form long-lasting T cell memory which can effectively prevent tumor recurrence. Most importantly, in vivo engineered CAR-macrophages also stimulated T cell memory against antigen-negative tumor cells through antigen spreading, which might effectively prevent the immune escape of heterogeneous tumor cells. Overall, we developed a platform of in vivo CAR-macrophages with dual roles as a tumor-killing effector cell and a recurrence-preventing vaccine.

bioengineering↗

bioRxiv2023

Metabolic Reprogramming via targeting ACOD1 promotes polarization and anti-tumor activity of human CAR-iMACs in solid tumors

The pro-inflammatory state of macrophages is crucial in conferring its role in combating tumor cells. That state is closely associated with metabolic reprogramming. Here we identified key metabolic genes regulating macrophage pro-inflammatory activation in a pooled metabolic gene knockout CRISPR screen. We found that KEAP1 and ACOD1 are strong regulators of the pro-inflammatory state, and therefore developed human ACOD1 knockout macrophages with our induced pluripotent stem cell-derived CAR-macrophage (CAR-iMAC) platform. The engineered iMACs showed stronger and more persistent polarization toward the pro-inflammatory state, more ROS production, and more potent phagocytosis and cytotoxic functions against cancer cells in vitro. Upon transplantation to ovarian or pancreatic cancer mouse models, ACOD1 depleted CAR-iMACs exhibited enhanced capacity in repressing tumors in vivo and prolonged the lifespan of mice. In addition, combining ACOD1-depleted CAR-iMACs with immune check point inhibitors (ICIs), such as the anti-CD47 antibody or anti-PD1 antibody resulted in stronger tumor suppressing effect. Mechanistically, the depletion of ACOD1 reduced the immunometabolite itaconate, allowing KEAP1 to prevent NRF2 from entering the nucleus to activate the anti-inflammatory program. This study demonstrates that ACOD1 is a new myeloid target for cancer immunotherapy and metabolically engineered human iPSC-derived CAR-iMACs exhibit enhanced polarization and anti-tumor functions in adoptive cell transfer therapies.

immunology↗

bioRxiv2022

A unified peptide array platform for antibody epitope binning, mapping, specificity and predictive off-target binding

Therapeutic antibody efficacy is largely determined by the target epitope. In addition, off-target binding can result in unanticipated side-effects. Therefore, characterization of the epitope and binding specificity are critical in antibody discovery. Epitope binning provides low-resolution of an antibody epitope and is typically performed as a cross-blocking assay to group antibodies into overlapping or non-overlapping bins. Epitope mapping identifies the epitope with high resolution but requires low throughput methods. In addition to binning and mapping, there is a need for a scalable and predictive approach to reveal off-target binding early in antibody discovery to reduce the risk of in vivo side effects. Peptide microarrays are an information-rich platform for antibody characterization. However, the potential of peptide microarrays in early-stage antibody discovery has not been realized because they are not produced at the scale, quality and format needed for reliable high-throughput antibody characterization. A unified, peptide library platform for high-resolution antibody epitope binning, mapping and predictive off-target binding characterization is described here. This platform uses highly scalable array synthesis and photolithography to synthesize more than 3 million addressable peptides. These arrays conform to a microplate format and each synthesis is qualified with mass spectrometry. Using this platform, a scalable approach to early-stage epitope and specificity characterization, with prediction of off-target interaction(s), is demonstrated using a panel of anti-HER2 monoclonal antibodies. This study highlights the prospect of this platform to improve antibody discovery productivity by generating epitope and specificity information much earlier with potentially hundreds of antibody clones.

bioengineering↗

bioRxiv2022

Deeply conserved super-enhancers maintain stem cell pluripotency in placental mammals

Despite pluripotent stem cells sharing key transcription factors, their maintenance involves distinct genetic inputs. Emerging evidence suggests that super-enhancers (SEs) can function as master regulatory hubs to control cell identity and pluripotency in humans and mice. However, whether pluripotency-associated SEs share a deep evolutionary origin in mammals remains elusive. Here, we performed comprehensive comparative epigenomic and transcription factor binding analyses among pigs, humans, and mice to identify pluripotency-associated SEs. Like typical enhancers, SEs displayed rapid evolution in mammals. We showed that BRD4 is an essential and conserved activator for mammalian pluripotency-associated SEs. Comparative motif enrichment analysis revealed 30 shared transcription factor binding motifs among the three species. The majority of the transcriptional factors that bind to identified motifs are known regulators associated with pluripotency. Further, we discovered three pluripotency-associated SEs (SE-SOX2, SE-PIM1, and SE-FGFR1) which displayed deep conservation in placental mammals and are sufficient to drive reporter gene expression in a pluripotency-dependent manner. Disruption of these conserved SEs through the CRISPR/Cas9 approach severely impaired the proliferative potential and the ability to form undifferentiated colonies. Our study provides insights into the understanding of conserved regulatory mechanisms underlying the maintenance of pluripotency as well as species-specific modulation of the pluripotency-associated regulatory networks in mammals. Significance statementSuper-enhancers (SEs) hold stronger power than regular enhancers to direct gene expression in the regulation of stem cell pluripotency. To dissect how pluripotency-associated SEs have evolved in mammals, we performed a systematic comparison of SEs among pigs, humans, and mice. Our analysis allowed the identification of three pluripotency-associated SEs (SE-SOX2, SE-PIM1, and SE-FGFR1) that are highly conserved in Placentalia (accounting for 94% of mammals) as well as many species-specific SEs. All three SEs were sufficient to direct pluripotency-dependent gene expression and disruption of each conserved SE caused the loss of stem cell pluripotency. Our work highlights a small number of highly conserved SEs essential for the maintenance of pluripotency.

cell biology↗

bioRxiv2021

rRNA Biogenesis Regulates Mouse 2C-like State by 3D Structure Reorganization of Peri-Nucleolar Heterochromatin

Nucleolus is the organelle for ribosome biogenesis and for sensing various types of stress. Its role in regulating stem cell fate is unclear. Here, we present multiple lines of evidence that nucleolar stress induced by interfering rRNA biogenesis can drive 2-cell stage embryo-like (2C-like) transcriptional program and induce an expanded 2C-like cell population in mouse embryonic stem (mES) cells. Mechanistically, the nucleolar integrity mediated by rRNA biogenesis maintains the normal liquid-liquid phase separation (LLPS) of nucleolus and the formation of peri-nucleolar heterochromatin (PNH). Upon rRNA biogenesis defect, the natural LLPS of nucleolus is disrupted, causing dissociation of NCL/TRIM28 complex from PNH and changes of epigenetic states and reorganization of the 3D structure of PNH, which leads to Dux, a 2C program transcription factor gene, to be released from the PNH region and activation of 2C-like program. Correspondingly, embryos with rRNA biogenesis defect are incompatible to develop from 2-cell (2C) to 4-cell embryos, with delayed repression of 2C/ERV genes and a transcriptome skewed toward earlier cleavage embryo signatures. Our results highlight that rRNA-mediated nucleolar integrity and 3D structure reshaping of PNH compartment regulates the fate transition of mES cells to 2C-like cells, and that rRNA biogenesis is a critical regulator during the 2-cell-to-4-cell transition of murine pre-implantation embryo development.

cell biology↗

bioRxiv2021

Regulatory start-stop elements in 5' untranslated regions pervasively modulate translation

Sequence elements within the 5 untranslated region (UTR) of eukaryotic genes, e.g. upstream open reading frames (uORFs), control translation of eukaryotic genes. We describe an element consisting of a start codon immediately followed by a stop codon which is distinct from uORFs in the lack of an elongation step. Start-stops have been described for specific cases, but their widespread impact has been overlooked. Start-stop elements occur in the 5UTR of 1, 417 human genes and are more often occupied with a ribosome than canonical uORFs or control sequences. Start-stops efficiently halt ribosomes without evidence for accelerated RNA turnover, therefore acting as a barrier for the scanning of the small ribosomal subunit and repressing downstream translation. Our results suggest a model by which the ribosome undergoes repeated cycles of termination and partial ribosomal recycling, during which the large subunit detaches, but the 40S subunit with the Met-tRNAiMet remains associated with the mRNA to be rejoined by the 60S subunit. Start-stop elements occur in many transcription factors and signaling genes, and affect cellular fate via different routes. We investigate the start-stop element in several genes, i.e. MORF4L1, SLC39A1, and PSPC1, and in more detail in ATF4.

systems biology↗

bioRxiv2021

Prenatal Alcohol and THC E-Cigarette Exposure Effects on Motor Development

It has been well established that prenatal alcohol exposure can lead to a wide range of neurological and behavioral deficits, including alterations in motor domains. However, much less is known about the effects of prenatal cannabis exposure on motor development, despite the fact that cannabis is the most commonly consumed illicit drug among women. Cannabis use among pregnant women has become increasingly popular given the wide-spread perception that consumption is safe during pregnancy. Moreover, alcohol and cannabis are commonly used together, even among pregnant women. Yet, few studies have explored the potential consequences of combined prenatal exposure on behavioral domains. Using our previously established model, pregnant Sprague-Dawley rats were exposed to vaporized alcohol, THC via e-cigarettes, the combination, or a vehicle from gestational days 5-20. Following birth, offspring were tested on early sensorimotor development, adolescent motor coordination, and adolescent activity levels. Prenatal e-cigarette THC exposure delayed sensorimotor development early in life and impaired motor coordination later in adolescence. However, combined prenatal alcohol and THC exposure produced hyperactivity among male offspring. These data suggest that prenatal cannabis exposure may lead to impaired motor skills throughout early development, and that combined exposure with alcohol during gestation may also lead to hyperactivity in adolescence. These findings have important implications for pregnant women and public policy.

pharmacology and toxicology↗

bioRxiv2020

Histone demethylase complexes KDM3A and KDM3B cooperate with OCT4/SOX2 to construct pluripotency gene regulatory network

The pluripotency gene regulatory network of porcine-induced pluripotent stem cells (piPSCs), especially in epigenetics, remains elusive. To determine this biological function of epigenetics, we cultured piPSCs in different culture conditions. We found that activation of pluripotent gene- and pluripotency-related pathways requires the erasure of H3K9 methylation modification which was further influenced by mouse embryonic fibroblast (MEF) served feeder. By dissecting the dynamic change of H3K9 methylation during loss of pluripotency, we demonstrated that the H3K9 demethylases KDM3A and KDM3B regulated global H3K9me2/me3 level and that their co-depletion led to the collapse of the pluripotency gene regulatory network. Immunoprecipitation-mass spectrometry (IP-MS) provided evidence that KDM3A and KDM3B formed a complex to perform H3K9 demethylation. The genome-wide regulation analysis revealed that OCT4 (O) and SOX2 (S), the core pluripotency transcriptional activators, maintained the pluripotent state of piPSCs depending on the H3K9 hypomethylation. Further investigation revealed that O/S cooperating with histone demethylase complex containing KDM3A and KDM3B promoted pluripotency genes expression to maintain the pluripotent state of piPSCs. Together, these data offer a unique insight into the epigenetic pluripotency network of piPSCs. SummaryErasure of H3K9 methylation in porcine pluripotent stem cells depends on the complex of transcription factors OCT4/SOX2 and histone demethylase KDM3A/KDM3B.

cell biology↗

bioRxiv2020

COMBINED VAPOR EXPOSURE TO THC AND ALCOHOL IN PREGNANT RATS: MATERNAL OUTCOMES AND PHARMACOKINETIC EFFECTS

Cannabis is the most frequently used illicit drug among pregnant women, yet the potential consequences of prenatal cannabis exposure on development are not well understood. Electronic cigarettes have become an increasingly popular route of administration among pregnant women, in part to users perception that e-cigarettes are a safer route for consuming cannabis products. Importantly, half of pregnant women who consume cannabis also report consuming alcohol, but research investigating co-consumption of these drugs is limited, particularly with current routes of administration. The purpose of this study was to establish a co-exposure vapor inhalation model of alcohol and THC in pregnant rats, to ultimately determine the effects on fetal development. Pregnant Sprague-Dawley rats were exposed to moderate doses of THC via e-cigarettes, alcohol, the combination, or vehicle daily from gestational days 5-20. Importantly, pharmacokinetic interactions of alcohol and THC were observed during pregnancy. Combined exposure consistently increased blood alcohol concentrations, indicating that THC alters alcohol metabolism. In addition, THC levels also increased over the course of pregnancy and THC metabolism was altered by alcohol. Alcohol, but not THC, exposure during pregnancy reduced maternal weight gain, despite no group differences in food intake. Neither prenatal alcohol nor THC exposure altered gestational length, litter size, sex ratio or birth weight. However, prenatal alcohol exposure delayed eye opening, and prenatal THC exposure decreased body weights during adolescence among offspring. These individual and synergistic effects suggest that this novel co-exposure vapor inhalation paradigm can effectively be used to expose pregnant dams, exerting some effects on fetal development, while avoiding nutritional confounds, birth complications, or changes in litter size. With this model, we have demonstrated that combining THC and alcohol alters drug metabolism, which could have important consequences on prenatal development.

pharmacology and toxicology↗

bioRxiv2020

Induced Pluripotent Stem Cell-derived CAR-Macrophage Cells with Antigen-dependent Anti-Cancer Cell Functions for Liquid and Solid Tumors

The Chimera antigen receptor (CAR)-T cell therapy has gained great success in the clinic. However, there are still major challenges for its wider applications in a variety of cancer types including lack of effectiveness due to the highly complex tumor microenvironment, and the forbiddingly high cost due to personalized manufacturing procedures. In order to overcome these hurdles, numerous efforts have been spent focusing on optimizing Chimera Antigen Receptors, engineering and improving T cell capacity, exploiting features of subsets of T cell or NK cells, or making off-the-shelf universal T cells. Here, we developed induced pluripotent stem cells (iPSCs)-derived, CAR-expressing macrophage cells (CAR-iMac). These cells showed antigen-dependent macrophage functions such as expression and secretion of cytokines, polarization toward the pro-inflammatory/anti-tumor state, and phagocytosis of tumor cells, as well as some in vivo anti-cancer cell activity for both liquid and solid tumors. This technology platform for the first time provides an unlimited source of iPSC-derived engineered CAR-macrophage cells which could be utilized to eliminate cancer cells or modulate the tumor microenvironment in liquid and solid tumor immunotherapy. One sentence summaryWe developed CAR-expressing iPSC-induced macrophage cells that have antigen-dependent phagocytosis and pro-inflammatory functions and anti-cancer cell activity for both liquid and solid tumor cells.

cell biology↗

bioRxiv2018

Quantifying multi-layered expression regulation in response to stress of the endoplasmic reticulum

The mammalian response to endoplasmic reticulum (ER) stress dynamically affects all layers of gene expression regulation. We quantified transcript and protein abundance along with footprints of ribosomes and non-ribosomal proteins for thousands of genes in cervical cancer cells responding to treatment with tunicamycin or hydrogen peroxide over an eight hour time course. We identify shared and stress-specific significant regulatory events at the transcriptional and post-transcriptional level and at different phases of the experiment. ER stress regulators increase transcription and translation at different times supporting an adaptive response. ER stress also induces translation of genes from serine biosynthesis and one-carbon metabolism indicating a shift in energy production. Discordant regulation of DNA repair genes suggests transcriptional priming in which delayed translation fine-tunes the early change in the transcriptome. Finally, case studies on stress-dependent alternative splicing and protein-mRNA binding demonstrate the ability of this resource to generate hypotheses for new regulatory mechanisms.

systems biology↗