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Biology subjects

Qin, Y.

Publications and source records attributed to Qin, Y..

At least 55 records · Page 3Linked to original sources

Enhancing Structure-aware Protein Language Models with Efficient Fine-tuning for Various Protein Prediction Tasks

Proteins are crucial in a wide range of biological and engineering processes. Large protein language models (PLMs) can significantly advance our understanding and engineering of proteins. However, the effectiveness of PLMs in prediction and design is largely based on the representations derived from protein sequences. Without incorporating the three-dimensional structures of proteins, PLMs would overlook crucial aspects of how proteins interact with other molecules, thereby limiting their predictive accuracy. To address this issue, we present S-PLM, a 3D structure-aware PLM that employs multi-view contrastive learning to align protein sequences with their 3D structures in a unified latent space. Previously, we utilized a contact map-based approach to encode structural information, applying the Swin-Transformer to contact maps derived from AlphaFold-predicted protein structures. This work introduces a new approach that leverages a Geometric Vector Perceptron (GVP) model to process 3D coordinates and obtain structural embeddings. We focus on the application of structure-aware models for protein-related tasks by utilizing efficient fine-tuning methods to achieve optimal performance without significant computational costs. Our results show that S-PLM outperforms sequence-only PLMs across all protein clustering and classification tasks, achieving performance on par with state-of-the-art methods that require both sequence and structure inputs. S-PLM and its tuning tools are available at https://github.com/duolinwang/S-PLM/.

bioinformatics↗

MIR192 Upregulates GLP-1 Receptor and Improves Statin-Induced Impairment of Insulin Secretion

Statins are a commonly prescribed cholesterol lowering drug class that can increase the risk of new-onset diabetes (NOD). To investigate the molecular mechanisms underlying this effect, we generated human induced pluripotent stem cells (iPSCs) from individuals identified from electronic health records of Kaiser Permanente of Northern California who were susceptible to developing NOD after statin initiation or controls who maintained stable fasting glucose on statin treatment. RNA-seq analysis of iPSCs incubated with atorvastatin, simvastatin or mock buffer for 24 hours identified the long non-coding RNA MIR194-2HG as a top candidate gene. Statin-induced increases in its expression were observed in NOD resistant controls, while statin-induced reductions occurred in NOD susceptible cases. MIR194-2HG encompasses two microRNA genes: MIR192 and MIR194-2. The mature microRNA miR-192-5p, derived from the 5 arm of MIR192, was predicted to bind the 3UTR of the glucagon like peptide 1 (GLP-1) receptor (GLP1R) transcript. Transfection of a rat insulinoma cell line INS-1 with a miR-192-5p mimic increased Glp1r transcript (1.41-fold) and protein (1.51-fold) levels compared to a scrambled control. Using a luciferase reporter containing the human GLP1R 3UTR, miR-192-5p overexpression similarly increased luciferase signal (1.44-fold). The miR-192-5p mimic enhanced glucose stimulated insulin secretion (GSIS) in response to GLP1R agonists (1.64-1.81-fold) and rescued simvastatin-induced GSIS impairment in INS-1 cells. Wild-type mice treated with miR-192 AAV8 had improved glucose sensitivity. Islets isolated from these mice exhibited enhanced GLP-1 potentiated GSIS during perifusion ex vivo. These effects were absent in the DIRKO (Glp1r/Gipr double knockout) mouse islets, consistent with the idea that miR-192 promotes GLP-1 mediated GSIS through GLP1R. These findings implicate MIR192 in statin-induced impairment of GSIS by modulating GLP1R, potentially contributing to the susceptibility to NOD in statin users.

cell biology↗

Multiplex-edited mice recapitulate woolly mammoth hair phenotypes

The woolly mammoth (Mammuthus primigenius) possessed a thick woolly coat and other cold-adaptive traits that enabled survival in harsh arctic environments. Current de-extinction efforts focus on genetically modifying the closely related Asian elephant to express woolly mammoth traits. In this study, we establish a multiplex-edited mouse model with modifications in genes associated with hair morphology and lipid metabolism, enabling insights into traits involved in developing woolly hair textures. Our optimized workflows achieved high editing efficiencies and produced genetically modified mice with simultaneous editing of up to seven different genes. Selected modifications include loss-of-function mutations in Fgf5, Tgm3, and Fam83g, among others. The resulting mice display exaggerated hair phenotypes including curly, textured coats, and golden-brown hair. This study advances methods of rapid establishment of complex genetic models. These approaches inform de-extinction efforts and research involving the genetic basis of mammalian hair development.

genetics↗

Heterochromatin fidelity is a therapeutic vulnerability in lymphoma and other human cancers

Genes involved in the regulation of chromatin structure are frequently disrupted in cancer, contributing to an aberrant transcriptome and phenotypic plasticity. Yet, therapeutics targeting mutant forms of chromatin-modifying enzymes have yielded only modest clinical utility, underscoring the difficulty of targeting the epigenomic underpinnings of aberrant gene regulatory networks. Here, we sought to identify novel epigenetic vulnerabilities in diffuse large B-cell lymphoma (DLBCL). Through phenotypic screens and biochemical analysis, we demonstrated that inhibition of the H3K9 demethylases KDM4A and KDM4C elicits potent, subtype-agnostic cytotoxicity by antagonizing transcriptional networks associated with B-cell identity and epigenetically rewiring heterochromatin. KDM4 demethylases associated with the KRAB zinc finger ZNF587, and their enzymatic inhibition led to DNA replication stress and DNA damage-induced cGAS-STING activation. Broad surveys of transcriptional data from patients also revealed KDM4 family dysregulation in several other cancer types. To explore this potential therapeutic avenue, we performed high-throughput small molecule screens with H3K9me3 nucleosome substrates and identified novel KDM4 demethylase inhibitors. AI-guided protein-ligand binding predictions suggested diverse modes of action for various small molecule hits. Our findings underscore the relevance of targeting fundamental transcriptional and epigenetic mechanisms for anti-cancer therapy. HIGHLIGHTSO_LIPhenotypic screens identified JIB-04 as a potent anti-cancer agent for multiple subtypes of diffuse large B-cell lymphoma C_LIO_LIJIB-04 binds and inhibits KDM4 demethylases resulting in epigenomic rewiring of heterochromatin C_LIO_LIKDM4 demethylases cooperate with KRAB zinc fingers to limit DNA replication stress, and KDM4 inhibition instigates DNA-damage and cGAS-STING activation in several human cancers C_LIO_LIHigh-throughput small molecule screens with semi-synthetic nucleosome substrates and AI-guided molecular docking simulations identify novel KDM4 inhibitors C_LI

genomics↗

Predicting Metabolic Dysfunction Associated Steatotic Liver Disease Risk Using Patient-Derived Induced Pluripotent Stem Cells

Background and AimsMetabolic Dysfunction Associated Steatotic Liver Disease (MASLD) is reversible at early stages, making early identification of high-risk individuals clinically valuable. Previously, we demonstrated that patient-derived induced pluripotent stem cells (iPSCs) harboring MASLD DNA risk variants exhibit greater oleate-induced intracellular lipid accumulation than those without these variants. This study aimed to develop an iPSC-based MASLD risk predictor using functional lipid accumulation assessments. MethodsWe quantified oleate-induced intracellular lipid accumulation in iPSCs derived from three cohorts of diverse ancestry: 1) CIRM cohort (20 biopsy-confirmed MASH cases, 2 biopsy-confirmed MASLD cases, 17 controls), 2) POST cohort (18 MASLD cases, 17 controls), and 3) UCSF cohort (4 biopsy-confirmed MASH cases, 8 controls). Lipid accumulation levels in the CIRM cohort were used to define an iPSC-based MASLD risk score, which was used to predict case/control status in the POST and UCSF cohorts. ResultsIn all three cohorts, lipid accumulation was higher in MASLD/MASH cases vs. controls (CIRM cases vs. controls 3.32 {+/-} 0.25 vs. 2.70 {+/-} 0.19 -fold change, p=0.06; POST cases vs. controls 3.63 {+/-} 0.33 vs. 2.70 {+/-} 0.31, p=0.05; and UCSF cases vs. controls 4.39{+/-}0.46 vs. 2.03{+/-}0.20, p=0.0002). The iPSC-based MASLD risk score achieved a sensitivity of 44% and specificity of 75% in the POST cohort and 75% and 100%, respectively, in the UCSF cohort. Differences in cohort disease severity and cardiometabolic profiles may explain performance variability. ConclusionWhile validation in larger cohorts is needed, these findings suggest that oleate-induced intracellular lipid accumulation in subject-derived iPSCs is predictive of MASH development. Additional cellular phenotypes and donor information should be explored to improve predictive accuracy to inform MASLD surveillance and prevention strategies.

cell biology↗

Loss of TMEM55B modulates lipid metabolism through dysregulated lipophagy and mitochondrial function

Lipophagy is a form of selective autophagy that targets the lipid droplets for lysosomal decay and has been implicated in the onset and progression of metabolic dysfunction-associated steatotic liver disease (MASLD). Factors that augment lipophagy have been identified as targets for MASLD therapeutic development. TMEM55B is a key regulator of lysosomal positioning which is critical for the lysosome fusion with the autophagosome, but less studied. Here, we demonstrate that inhibition of TMEM55B in murine models accelerates MASLD onset and progression. In cellular models, TMEM55B deficiency enhances lipophagy, leading to increased fatty acid release from lysosomes to mitochondria but simultaneously impairs mitophagy, causing an accumulation of dysfunctional mitochondria. This imbalance leads to increased lipid accumulation and oxidative stress, worsening MASLD. These findings underscore the importance of lysosomal positioning in lipid metabolism and suggest that augmenting lipophagy may exacerbate disease in the context of mitochondrial dysfunction.

cell biology↗

Stacked Human Arterial Endothelial Cells Generate Atherosclerotic Fatty Streaks and Release Proinflammatory Cytokines

Fatty streaks are the first sign of atherosclerosis. They consist of lipid-containing foam cells, which were believed to be derived from the monocytes in the blood through the leaky endothelium, and from the vascular smooth muscle cells migrating into the intima from the media. Here, we showed that fatty streaks can also be formed by the stacked human arterial endothelial cells (HAECs) cultured in vitro. Via SEM we revealed a novel cell phenotype (coralthelial) that forms a streak/coral-like structure. We observed accumulation of lipids in the coralthelial cell and increased Golgi and coat protein II markers in its nucleus. Additionally, proinflammatory cytokines were upregulated in these cells, likely due to Golgi nuclear translocation and subsequently increased expression of the ribosomal protein RPL23 in the nucleus. We demonstrated, for the first time, that the atherosclerotic fatty streak-like structure can be generated from the stacked HAECs, which also create a proinflammatory microenvironment. Significance StatementOur work presents a novel perspective on atherosclerotic fatty streak formation, a critical early event in atherosclerosis development. We demonstrate, for the first time, that human arterial endothelial cells (HAECs) can transform into a novel phenotype, termed "coralthelial cells". These cells contribute to fatty streak formation, and produce proinflammatory cytokines through the relocation of RPL23 with the Golgi apparatus to the nucleus. This finding provides a new cellular mechanism by which endothelial cells initiate atherosclerosis, independent of traditional monocyte-derived foam cells. By enriching established paradigms, our research not only opens new avenues for therapeutic intervention targeting endothelial cells but also enhances understanding of vascular diseases and provides potential diagnostic and prognostic markers for atherosclerosis.

cell biology↗

Soluble guanylyl cyclase, the NO-receptor, regulates endothelium-dependent vascular relaxation via its transnitrosation activity.

We previously demonstrated that the NO-receptor soluble guanylyl cyclase (GC1) has the ability to transnitrosate other proteins in a reaction that involves, in some cases, oxidized Thioredoxin 1 (oTrx1). This transnitrosation cascade was established in vitro and we identified by mass spectrometry and mutational analysis Cys 610 (C610) of GC1 -subunit as a major donor of S-nitrosothiols (SNO). To assay the relevance of GC1 transnitrosation under physiological conditions and in oxidative pathologies, we studied a knock-in mouse in which C610 was replaced with a serine (KI C610S) under basal or angiotensin II (Ang II)-treated conditions. Despite similar GC1 expression and NO-stimulated cGMP-forming activity, the Ang II-treated KI mice displayed exacerbated oxidative pathologies including higher mean arterial pressure and more severe cardiac dysfunctions compared to the Ang II-treated WT. These phenotypes were associated with a drastic decrease in global S-nitrosation and in levels of SNO-Trx1 and SNO-RhoA in the KI mice. To investigate the mechanism underlying the dysregulation of blood pressure despite an intact NO-cGMP axis, pressure myography and in vivo intravital microscopy were conducted to analyze the vascular resistance tone. Both approaches indicated that, even in the absence of oxidative stress, the single mutation C610S led to a significant deficiency in acetylcholine-induced vasorelaxation while smooth muscle relaxation in response to NO remained unchanged. These findings indicate that the C610S mutation uncoupled the two NO signaling pathways involved in the endothelium and smooth muscle vasorelaxation and suggest that GC1-dependent S-nitrosation is a key player in endothelium-derived hyperpolarization.

biochemistry↗

Multimodal integration of single cell ATAC-seq data enables highly accurate delineation of clinically relevant tumor cell subpopulations

Accurately deciphering tumor cellular heterogeneity is crucial for developing effective treatments. While single-cell epigenomics assays offer powerful insights into studying tumor heterogeneity beyond the transcriptional level, their application remains a significant challenge. To address this, we introduce Multimodal-based Analysis of scATAC-Seq data (MAAS), a method designed to identify functional tumor cell subpopulations and reconstruct their lineages from single-cell sequencing assay for transposase-accessible chromatin (scATAC-seq). MAAS uniquely integrates multimodal information, encompassing chromatin accessibility, copy number variations (CNVs), and single-nucleotide variants, through self-expressive multimodal matrix factorization. MAAS outperforms existing methods in accuracy and robustness on both simulated and real datasets. When applied to multiple glioma scATAC-seq datasets, MAAS uncovered a previously hidden tumor cell subpopulation resistant to temozolomide treatment. Furthermore, MAAS effectively detected clinically relevant subpopulations with low CNVs, such as those found in pediatric ependymoma and B-cell lymphoma. Additionally, we developed a novel MAAS-derived clinical signature that provides superior prognostic prediction than traditional clinicopathologic features across multiple cancer types. In summary, MAAS significantly advances the identification of clinically relevant tumor cell subpopulations, thereby accelerating the discovery of potential therapeutic targets.

bioinformatics↗

CureSCi Metadata Catalog - finding and harmonizing studies for secondary analysis of hydroxyurea use for sickle cell disease

ObjectivesSickle cell disease (SCD) is a rare group of inherited red blood cell disorders that affect hemoglobin, resulting in serious multi-system complications. The limited number of patients available to participate in research studies can inhibit investigating sophisticated relationships. Secondary analysis is a research method that involves using existing data to answer new research questions. Data harmonization enables secondary analysis by combining data across studies, especially helpful for rare disease research where individual studies may be small. The National Heart, Lung, and Blood Institute Cure Sickle Cell Initiative (CureSCi) Metadata Catalog is a web-based tool to identify SCD study datasets for conducting data harmonization and secondary analysis. We present a proof-of-concept secondary analysis to explore factors associated with discontinuation of hydroxyurea, a safe and effective first line SCD therapy, to illustrate the utility of the CureSCi Metadata Catalog to expedite and enable more robust SCD research. MethodsWe performed secondary analysis of SCD studies using a multi-step workflow: develop research questions, identify study datasets, identify variables of interest, harmonize variables, and establish an analysis method. A harmonized dataset consisting of eight predictor variables across five studies was created. Secondary analysis involved a generalized linear model was employed to identify factors that significantly impact hydroxyurea discontinuation. ResultsThe CureSCi Metadata Catalog provided a platform to efficiently find relevant studies and design a harmonization strategy to prepare data for secondary analysis. Multivariate analysis of the harmonized identified that patients who are older, are female, had a history of blood transfusion therapy, had episodes of acute chest syndrome, and had the SC sickle cell genotype are more likely to stop hydroxyurea treatment. ConclusionThis secondary analysis provides a template for how the CureSCi Metadata Catalog expedites dataset discovery of sickle cell studies for identifying relationships between variables or validating existing findings.

bioinformatics↗

Association study of Plasmodium falciparum Acetyl-CoA Synthetase Mutations S868G and V949I with antimalarial drugs

Plasmodium falciparum acetyl-CoA synthetase (PfACAS) protein is an important source of acetyl-CoA. We detected the mutations S868G and V949I in PfACAS by whole-genome sequencing analysis in some recrudescent parasites after antimalarial treatment with artesunate and dihydroartemisinin-piperaquine, suggesting that they may confer drug resistance. Using CRISPR/Cas9 technology, we engineered parasite lines carrying the PfACAS S868G and V949I mutations in two genetic backgrounds and evaluated their susceptibility to antimalarial drugs in vitro. The results demonstrated that PfACAS S868G and V949I mutations alone or in combination were not enough to provide resistance to antimalarial drugs.

microbiology↗

Chromosome-level genome assembly of autotetraploid Selenicereus megalanthus and gaining genomic insights into the evolution of trait patterning in diploid and polyploid pitaya species

Yellow pitaya (Selenicereus megalanthus, 2n=4x=44) breeding remains severely hindered due to lacking a reference genome. Here we report yellow pitayas high-quality chromosome-level genome assembly and link the phenotypic trait with genomic data, based on Hi-C, ATAC, and RNA-seq data of specific tissues. We declared yellow pitaya as an autotetraploid with a 7.16 Gb genome size (harboring 27,246 high confidence genes) and majorly evolved from diploid ancestors, which remains unknown. Beyond generating the genome assembly, we explored the 3D chromatin organization which revealed insights into the genome, compartments A (648 and 519), compartments B (728 and 1064), topologically associated domains-TADs (3376 and 2031), and varying numbers of structural variations (SVs) in diploid and polyploid pitaya species, respectively. Overall, TAD boundaries were enriched with the motifs of AP2, WRKY18/60/75, MYB63/116, PHL2, and GATA8 in both pitaya species. By linking the open chromatin genomic structure to function, we identified the major changes in betalains biosynthesis pathway in diploid and polyploid pitaya. Moreover, the higher genetic expression of SmeADH1 [Chr11, Compartment A (135400000 - 135500000), genes inside the TAD region (135480000 - 135520000)], and lower expression of HuDOPA [Chr11, Compartment A (87100000 - 87200000), genes inside the TAD region (87160000-87200000)] acts as a key regulator of yellow and red color on the pericarp of polyploid and diploid pitaya, respectively. In addition, higher expression of HuCYP76AD1 genes in diploid pitaya and lower expression of SmeCYP76AD1 in polyploid pitaya potentially created the difference in the oxidase process that led to the production of betacyanin and betaxanthin, respectively. Furthermore, our results revealed not only the type of motifs that play a potential role in trait patterning but we also further uncovered that motif count in TAD-boundaries may impact the gene expression within the TAD regions of diploid and polyploid pitaya. Our valuable genomic resource and comparison of 3D euchromatin architecture of diploid and polyploid pitaya species will not only aid in the advancement of molecular breeding efforts but also offer insights into the organization of genomes, SVs, compartmentalization (A and B), and TADs, which have the potential to strengthen the idea of TADs-based trait improvement to achieve global food security.

plant biology↗

Deep generative models generate mRNA sequences with enhanced translation capacity and stability

Despite the tremendous success of messenger RNA (mRNA) COVID-19 vaccines, the extension of this modality to a broader spectrum of diseases necessitates substantial enhancements, particularly in the design of mRNAs with elevated expression levels and extended durability. Here we present GEMORNA, a deep generative model designed to generate novel mRNA coding sequences (CDSs) and untranslated regions (UTRs) with superior translation capacity, comparable to the sophisticated task of language translation and free-form poetry composition with accurate grammar and semantics. Our AI model was trained on an extensive collection of RNA sequences from diverse families, further enhanced with labeled data to refine its performance. Remarkably, we demonstrate that our AI-generated mRNAs exhibited 8.2-fold and 15.9-fold increases in firefly luciferase expression compared to benchmark mRNAs in two different cell types. Additionally, Our AI- designed COVID-19 mRNA vaccine elicited a 4-fold increase in anti-COVID antibody titer in mice relative to BNT162b2. Furthermore, GEMORNAs versatility extends to circular mRNA design, which we facilitated a 27-fold increase in human erythropoietin protein expression in vivo than a systematically optimized benchmark sequence. We also created circular mRNAs with substantial improvements in expression levels, durability and anti-tumor cell cytotoxicity in mRNA-transduced CAR-T cells compared with an experimentally validated benchmark. In summary, GEMORNA generates novel mRNA sequences with significant performance improvements and has the potential to enable a wide range of therapeutic and vaccine applications.

synthetic biology↗

Calorie Restriction Induces Degeneration of Neurons with Mitochondrial DNA Depletion by Altering ER-Mitochondria Calcium Transfer

Mitochondrial DNA (mtDNA) mutations and/or depletion are implicated in epilepsy and many neurodegenerative diseases. However, systematic investigation into how mtDNA alterations relate to epilepsy and neural degeneration is needed. Here, we established a mouse model where in mtDNA depletion induced by Herpes Simplex Virus Type 1 (HSV-1) protein-UL12.5 in the brain led to an epileptic phenotype characterized by abnormal electroencephalography (EEG) patterns and increased neural excitability in hippocampus. We also found that UL12.5 mediated mtDNA depletion in neurons in vitro (rho-) causes epilepsy-like abnormal EEG. Caloric restriction (CR) is a strategy proven to reduce epileptic activity, however CR mimetic 2-deoxy-D-glucose (2-DG), induced degeneration in mtDNA depleted neurons. Mechanistically, mtDNA depletion increased mitochondria-endoplasmic reticulum (ER) contacts, facilitating CR-induced mitochondrial calcium overload. Rho- neurons did not show changes in mitochondrial motility or membrane potential. Our study revealed an unexpected axis of mtDNA depletion, ER-mitochondrial contacts, and calcium overload in the rho- neuron model. This is the first description of animal and neuronal models of mitochondrial epilepsy. Our findings with these models suggest that CR may not be a viable clinical intervention in patients with mtDNA depletion.

cell biology↗

Acetyl-CoA Synthetase Mutations S868G and V949I Do Not Confer Resistance to Antimalarial Drugs in vitro in Plasmodium falciparum.

Plasmodium falciparum acetyl-CoA synthetase (PfACAS) protein is an important source of acetyl-CoA. We detected the mutations S868G and V949I in PfACAS by whole-genome sequencing analysis in some recrudescent parasites after antimalarial treatment with artesunate and dihydroartemisinin-piperaquine, suggesting that they may confer drug resistance. Using CRISPR/Cas9 technology, we engineered parasite lines carrying the PfACAS S868G and V949I mutations in two genetic backgrounds and evaluated their susceptibility to antimalarial drugs in vitro. The results demonstrated that PfACAS S868G and V949I mutations alone or in combination were not enough to provide resistance to antimalarial drugs.

microbiology↗

Pandemic Vibrio parahaemolyticus wave succession by gene loss

While spontaneous mutation and gene acquisition are well-established drivers of pathogen adaptation, the role of gene loss remains underexplored. Here, we investigated the emergence and diversification of the pandemic clone (PC) of Vibrio parahaemolyticus through large-scale phylogenomic analysis of 8,684 global isolates. The PC rapidly acquired multiple marker genes and genomic islands, subsequently diverging into successive sublineages mediating independent waves of cross-country transmission, as also observed in V. cholerae. Wave succession in the last two decades was driven by loss of putrescine utilization (Puu) genes, conferring phenotypic advantages for environmental adaptation (enhanced biofilm formation) and human transmission (increased cell adhesion/intestinal colonization, reduced virulence), consistent with the virulence trade-off hypothesis. We identified Puu-gene loss in multiple bacterial genera, with effects on biofilm and adhesion replicated in V. cholerae and Escherichia coli, suggesting convergent evolution and universal phenotypic effects. Our results highlight the indispensable role of gene loss in bacterial pathogen adaptation.

microbiology↗

A Novel Regulation on the Developmental Checkpoint Protein Sda that Controls Sporulation and Biofilm Formation in Bacillus subtilis

Biofilm formation by Bacillus subtilis is triggered by an unusually simple environmental sensing mechanism. Certain serine codons, the four TCN codons (N for A, T, C, or G), in the gene for the biofilm repressor SinR caused lowered SinR translation and subsequent biofilm induction during transition from exponential to stationary growth. Global ribosome profiling showed that ribosomes pause when translating the four UCN (U for T on the mRNA) serine codons on mRNA, but not the two AGC/AGU serine codons. We proposed a serine codon hierarchy (AGC/AGT vs TCN) in that genes enriched in the TCN serine codons may experience reduced translation efficiency when serine is limited. In this study, we designed an algorithm to score all protein-coding genes in B. subtilis NCIB3610 based on the serine codon hierarchy. We generated a short list of 50 genes that could be subject to regulation by this novel mechanism. We further investigated one such gene from the list, sda, which encodes a developmental checkpoint protein regulating both sporulation and biofilm formation. We showed that synonymously switching the TCN serine codons to AGC in sda led to delayed biofilm formation and sporulation. This engineered strain also outgrew strains with other synonymously substituted sda alleles (TCN) in competition assays for biofilm formation and sporulation. Lastly, we showed that the AGC serine codon substitutions in sda elevated the Sda protein levels. This serine codon hierarchy-based novel signaling mechanism could be exploited by bacteria in adapting to stationary phase and regulating important biological processes. ImportanceGenome-wide ribosome profiling in Bacillus subtilis shows that under serine limitation, ribosomes pause on the four TCN (N for A, C, G, and T), but not AGC/AGT serine codons, during translation at a global scale. This serine codon hierarchy (AGC/T vs TCN) differentially influences translation efficiency of genes enriched in certain serine codons. In this study, we designed an algorism to score all 4000+ genes in the B. subtilis genome and generated a list of 50 genes that could be subject to this novel serine codon hierarchy-mediated regulation. We further investigated one such gene, sda, encoding a developmental check point protein. We show that sda and cell developments controlled by Sda are also regulated by this novel mechanism.

genetics↗

Efficient and durable gene activation by Cas9-mediated epigenome editing in vivo

Epigenome editing technology holds great promise for treating diverse genetic disorders. While a series of advances has been made on epigenetic silencing using programmable editors, little progress has been made in leveraging epigenetic activation for therapeutic application. Here we demonstrate epigenetic activation of the LAMA1 gene for the treatment of LAMA2-CMD, a severe congenital muscle dystrophy (CMD) caused by biallelic mutations in the LAMA2 gene. LAMA1 is a sister homologue that is known to compensate for the function of LAMA2. However, supplementing LAMA1 or LAMA2 gene via viral platform is not feasible due to the large size of their coding sequences. Through a single administration of our (Adeno-associated virus) AAV vector encoding all the necessary elements for epigenetic activation, a platform termed CRISPR guide-nucleotide directed modulation (GNDM), we observed significant LAMA1 gene upregulation and phenotype improvements in DyW mice, a severe disease model of LAMA2-CMD. Notably, sustained expression of the GNDM gene and subsequent activation of the LAMA1 gene persisted beyond analyzed period of one year despite immune recognition of the GNDM protein by the host immune system. Regulatory T (Treg) cells appeared to facilitate tolerance to GNDM in the transduced muscle tissue. The muscle-tropic AAV capsid exhibited desired vector biodistribution and promising pharmacodynamics with good safety profiles in adult non-human primates (NHPs). Moreover, administration to juvenile NHPs demonstrated superior pharmacodynamics compared to adults, even at half the adult dose, suggesting safer and more effective therapeutic outcomes in mostly pediatric LAMA2-CMD patients. Our approach holds broad applicability for a range of loss-of-function genetic disorders and could offer a therapeutic breakthrough where active epigenome brings clinical benefit.

bioengineering↗