Biology subjects

Srinivasan, S.

Publications and source records attributed to Srinivasan, S..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Targeting CREB remodels the immune microenvironment to enhance immunotherapy responses in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) remains a challenging disease in need of improved treatments. Cyclic adenosine monophosphate response element binding protein 1 (CREB) is an emerging therapeutic target whose oncogenic effects in PDAC have been largely attributed to a key molecular interplay between oncogenic KrasG12D/+ (Kras*) and chronic inflammation driving irreversible acinar to ductal reprogramming. Here, we demonstrate that CREB activation fosters tumor associated macrophage (TAM) mediated immunosuppression and promotes PDAC growth in an aggressive LSL-KrasG12D/+;Trp53R172H/+;Pdx1Cre/+(KPC) genetically engineered mouse model. Selective deletion of CREB (Crebfl/fl) in KPC(KPCC-/-) mice attenuates primary disease burden. Unbiased transcriptomic analysis and validation using diverse molecular, genetic and pharmacological approaches in vitro and in vivo identify CREB-mediated transcriptional regulation of leukemia inhibitory factor (Lif) as one of the potential mediators of tumor cell-macrophage crosstalk promoting a pro-tumor polarization of TAMs, thereby attenuating the infiltration of effector T cells. Mechanistically, cancer cell derived LIF facilitates an immunosuppressive, pro-tumorigenic state. Importantly, pharmacological targeting of the CREB-LIF signaling axis between cancer cells and macrophages, using a CREB-specific inhibitor (CREBi), significantly suppresses tumor growth and sensitizes PDAC to immunotherapy, highlighting the therapeutic potential of this treatment combination to improve outcomes in this aggressive disease.

cancer biology↗

bioRxiv2025

NK2R signaling governs intestinal lipid mobilization and mucosal inflammation

Neuropeptidergic control of lipid metabolism is conserved and increasingly implicated in metabolic diseases, but receptor-level mechanisms remain unclear. Here we identify the neurokinin-2 receptor (NK2R) as a central node linking tachykinin signals to intestinal lipid mobilization, epithelial composition, and mucosal inflammation. Across complementary genetic and pharmacological perturbations, modulation of NK2R drives bidirectional effects. Loss or blockade of NK2R increases postprandial triglyceridemia and expands intestinal lipid stores, whereas agonism suppresses chylomicron output, reduces adiposity, and improves glycemia in diet-induced obesity. Transcriptomic and cellular analyses indicate coordinated upregulation of lipid-metabolic programs with a concomitant dampening of immune pathways in the absence of NK2R, accompanied by sex-specific remodeling of secretory lineages and male-biased protection from colitis. NK2R signaling also shaped the fecal microbiota in a genotype- and diet-dependent manner, highlighting crosstalk among neuropeptide signaling, epithelial physiology, and host-microbe interactions. These findings position NK2R as a molecular switch for intestinal lipid handling and mucosal inflammation and suggest that NK2R-targeted agonists or antagonists could be deployed as context- and sex-dependent therapeutic strategies for metabolic disease and inflammatory bowel disease.

physiology↗

bioRxiv2025

A hidden protamine PTM code in sperm generates heterogeneous chromatin states and finetunes reproductive fitness

Traditionally, the sperm genome is thought to be packaged by protamines into a uniformly compact and inert chromatin structure. Here, we challenge this long-standing view by demonstrating that protamine post-translational modifications (PTMs) present on distinct protamine molecules create discrete protamine-DNA chromatin states, ranging from weak to tightly associated chromatin configurations. Loss of these modifications alters protamine-DNA interactions in vitro and in vivo, compromising sperm chromatin integrity and impairing fertility. Therefore, these findings demonstrate that protamines do not merely serve as inert packaging proteins; rather protamine PTMs establish functional heterogeneity within sperm chromatin, creating compartment-like domains analogous to those in somatic cells. Thus, PTMs allow protamines to do more than simply compact the paternal genome--they likely encode a molecular blueprint that orchestrates the timely unpacking and reorganization of the paternal genome after fertilization.

molecular biology↗

bioRxiv2025

Recurrent Breast Cancer Cells Depend on De novo Pyrimidine Biosynthesis to Suppress Ferroptosis

Breast cancer recurrence remains a major clinical challenge, often associated with therapy resistance and altered metabolic states. To define metabolic vulnerabilities of recurrent disease, we performed a CRISPR knockout screen targeting 421 metabolic genes in paired primary and recurrent HER2-driven breast cancer cell lines. While both primary and recurrent tumors shared dependencies on core metabolic pathways, recurrent tumors exhibited selective essentiality for the de novo pyrimidine synthesis pathway, including Cad, Dhodh, and Ctps. Pharmacologic inhibition of the rate-limiting enzyme DHODH with BAY-2402234 selectively impaired the growth of recurrent tumor cells, while primary tumor cells were relatively resistant. BAY treatment robustly inhibited pyrimidine synthesis in all lines, but only recurrent cells underwent iron-dependent lipid peroxidation and ferroptotic cell death. Lipidomic profiling revealed enrichment of polyunsaturated ether phospholipids in recurrent cells, which may predispose them to ferroptosis. A sensitizer CRISPR screen in primary cells further identified nucleotide salvage and lipid metabolic pathways as modifiers of DHODH inhibitor sensitivity. Stable isotope tracing and nutrient depletion experiments showed that primary cells can compensate for DHODH inhibition through nucleotide salvage, whereas recurrent cells exhibit impaired salvage capacity, likely due to reduced expression of Slc28/Slc29 nucleoside transporters. Together, these findings reveal that breast cancer recurrence is associated with increased dependence on de novo pyrimidine synthesis to suppress ferroptosis, highlighting a therapeutically actionable metabolic vulnerability in recurrent disease.

cancer biology↗

bioRxiv2025

Benchmarking Framework to Catalyze Individual Human Genome Projects

Individual human genome projects still aim for chromosome-level gapless assemblies, which rely on high-coverage reads from multiple long-read sequencing platforms using a multiplicity of assembly pipelines. Moreover, the dependence on DNA derived from primary cell lines for these assemblies makes such projects prohibitively expensive to scale for individual genome initiatives and to catalyze clinical applications. Over the past decades, genome assembly quality has advanced remarkably from draft assemblies in the early 2010s, to chromosome-level assemblies using error-prone long reads in the late 2010s, to the recent T2T gapless assemblies enabled by high-quality next-generation long-read technologies. That said, a systematic evaluation of trade-offs from assemblies obtained at various coverages, starting at 3x, from a single long-read sequencing platform, is critical for developing a cost-effective and practical strategy for catalyzing individual genome initiative. Here, by assembling contigs at various coverage levels through downsampling of existing PacBio HiFi reads from three individuals, we demonstrate that high-quality assemblies, as measured by standard assembly metrics and DNA-level linearity relative to a reference across most chromosomes (developed inhouse), can be achieved at approximately 12x coverage. Interestingly, starting at coverages as low as 6x, assembly metrics, including BUSCO scores and DNA-level linearity, begin to saturate, suggesting minimal trade-offs. Furthermore, we show that known structural variants (e.g., the 8p23.1 inversion) can be reliably identified even at 6x coverage. Together, these results suggest that cost-effective strategies can be developed to advance individual genome initiatives potentially from PacBio HiFi reads from a single SMRT cell per human genome.

bioinformatics↗

bioRxiv2025

Differential Tissue Coupled Powering for Battery-Free Injectable Electroceuticals

Electroceutical implants that deliver targeted neural stimulation have shown therapeutic potential for a wide range of neurological and peripheral disorders, yet wirelessly powering ultra-miniaturized, fully injectable systems remains a critical challenge. Here we report a Thread-like Injectable Neural TechnologY (TINY), powered via a differential tissue-coupled powering (DTCP) scheme. DTCP employs mid-frequency differential potentials applied across external electrodes on a compact, wearable transmitter to deliver energy through tissue to an ultra-miniaturized, thread-like implant that integrates a custom ASIC and PEDOT-coated receiver and stimulation electrodes. Benchtop experiments in agar phantoms characterize the power-transfer efficiency (PTE) and reveal that PTE increases with implant length while maintaining strong tolerance to angular misalignment. In vivo tests in rat hindlimbs further demonstrate wireless activation of the sciatic nerve through tissue at centimeter-scale depths, confirming effective transcutaneous energy delivery for neurostimulation. A 20-day implantation study shows stable positioning of the device with minimal tissue response, indicating excellent chronic compatibility. These findings address long-standing challenges in wirelessly powering injectable electroceuticals and establish DTCP as a scalable and alignment-robust powering strategy for future minimally invasive neuromodulation therapies.

bioengineering↗

bioRxiv2025

RiboTRAP-seq identifies spatially distinct functions for the anterior and posterior intestine in immune and metabolic regulation in C. elegans

The intestine integrates food-derived cues to coordinate organismal physiology, yet the molecular specialization of discrete regions along the intestinal epithelium remains unclear. Here, we generate cell type-specific translatomes of the Caenorhabditis elegans intestine during fasting and refeeding using discrete promoters for the anterior quartet of intestinal cells (INT1) and the remaining 8 pairs of intestinal cells (INT2-9). We found that the anterior-most INT1 cells are a translationally distinct intestinal sub-compartment that is particularly enriched for immune-and stress-response genes. Functional assays using novel INT1-specific genes emerging from this study reveal that these specialized cells play a previously unappreciated role in pathogen avoidance and organismal survival. A second critical function of INT1 cells is their role in sensing and responding to the contents of the gut lumen. We show that luminal pyruvate is the key signal linking bacterial nutrients in the gut, to secretion of the gut insulin antagonist INS-7. These findings establish INT1 as sentinel enteroendocrine cells that integrate metabolic and immune cues to couple food status with immune and endocrine responses. Our studies also provide a rich resource for dissecting segment-specific intestinal biology, an overlooked and fertile area for future research.

physiology↗

bioRxiv2025

PLI Analyzer for Data-driven Validation of AI Predicted Biomolecular Interfaces

PLI-Analyzer is a computational tool for detailed analysis of protein, RNA, and DNA interaction interfaces, combining atomic-level contact detection with domain annotations from UniProt and InterPro. It offers customizable interaction thresholds, residue-level output, and compatibility with AI-generated structures, enabling precise validation and interpretation of contact dynamics. We applied PLI-Analyzer to evaluate high-quality protein-protein complexes predicted by AlphaFold-3 and Boltz-2, revealing notable differences in predicted interfaces and confidence scores. These findings highlight current limitations in generative structure models specifically for macromolecular complexes and underscore the need for robust, domain-informed evaluation frameworks in structural bioinformatics.

bioinformatics↗

bioRxiv2025

Active regulation of the epidermal growth factor receptor by the membrane bilayer

Cell surface receptors transmit information across the plasma membrane to connect the extracellular environment to intracellular function. While the structures and interactions of the receptors have been long established as mediators of signaling, increasing evidence suggests that the membrane itself plays an active role in both suppressing and enhancing signaling. Identifying and investigating this contribution has been challenging owing to the complex composition of the plasma membrane. We used cell-free expression to incorporate the epidermal growth factor receptor (EGFR) into nanodiscs with defined membrane compositions and characterized ligand-induced transmembrane conformational response and interactions with signaling partners using single-molecule and ensemble fluorescence assays. We observed that both the transmembrane conformational response and interactions with signaling partners are strongly lipid dependent, consistent with previous observations of electrostatic interactions between the anionic lipids and conserved basic residues near the membrane adjacent domain. Strikingly, the active conformation of EGFR and high levels of ATP binding were maintained regardless of ligand binding with high anionic lipid content typical of cancer cells, where EGFR signaling is enhanced. In contrast, the conformational response was suppressed in the presence of cholesterol, providing a mechanism for its known inhibitory effect on EGFR signaling. Our findings introduce a model of EGFR signaling in which the lipid environment can override ligand control, providing a biophysical basis for both robust EGFR activity in healthy cells and aberrant activity under pathological conditions. The membrane-adjacent protein sequence, likely responsible for the lipid dependence, is conserved among receptor tyrosine kinases, suggesting that active regulation by the plasma membrane may be a general feature of this important class of proteins.

biophysics↗

bioRxiv2025

Immune-Competent 3D Bioengineered Colons for Functional Interrogation of Neuroinflammation-Induced Colonic Dysmotility

Functional gastrointestinal disorders (FGIDs) affect [~]40% of the global population and are frequently characterized by colonic dysmotility. Symptomatic manifestations of colonic dysmotility significantly reduce quality of life in inflammatory bowel disease (IBD), diabetes, and Gulf War Illness (GWI). Current in vitro models lack the integration of functional physiology with immune and neuronal complexity required to establish causal links between neuroinflammation and dysmotility. Here, an immune-competent bioengineered colon assembloid is introduced that integrates multiple cell types of the external colonic wall, along with functional readouts of motility. Within bioengineered colon assembloids, various inflammatory insults resulted in enteric neuroinflammation, cascading to changes in colonic motility. Key mechanisms of dysmotility following inflammatory insult within the bioengineered colon assembloids included impaired neuronal regeneration, and aberrant smooth muscle remodeling. The bioengineered colon assembloid model mimicked diverse aspects of enteric neuroinflammation. Ultimately, the platform offers a physiologically relevant avenue to interrogate neuroimmune crosstalk and dissect mechanisms of colonic dysmotility, paving the way to new therapeutic strategies to improve colonic motility.

bioengineering↗

bioRxiv2025

Reprogramming of Cellular Plasticity via ETS and MYC Core-regulatory Circuits During Response to MAPK Inhibition in BRAF-mutant Colorectal Cancer

BackgroundAberrant enhancer dynamics play a critical role in the initiation and progression of colorectal cancer (CRC). BRAFV600E-mutated metastatic CRC may be a unique subtype, exhibiting a strong epigenetic phenotype. Interestingly, bromodomain 2, a reader protein for H3K27ac-marked enhancers, was found to be synthetically lethal in CRC with BRAF + EGFR inhibition. DesignWe evaluated the effectiveness of targeting aberrant enhancers with bromodomain and extraterminal (BET) + MAPK pathway inhibitors in patient-derived xenograft models of metastatic CRC, followed by comprehensive profiling of transcriptomic and chromatin dynamics upon BET inhibitor combination treatment. ResultsThe combination of BET and standard MAPK inhibitors has demonstrated improved efficacy against BRAFV600E CRC and selective improvements against RAS-mutant CRC in vivo. We showed that BET + MAPK inhibition induced a profound downregulation of the MAPK signaling pathway compared to MAPK inhibition alone. The loss of activation signal on enhancers, as determined by H3K27ac, led to dysregulation of core-regulatory circuitries of CRC, especially loss of the auto-regulatory mechanism of the MAPK downstream E26 transformation-specific transcription factor family. Single nucleus multiome (RNA + ATAC) sequencing further distinguished differential transcriptomic and chromatin dynamics at cell type levels. Profound downregulation of well-differentiated cell types confirmed deep inhibition of MAPK signaling and downstream transcription factors. On the other hand, dedifferentiated cell populations were abundant after MAPK or combination inhibition, suggesting therapy-induced cell state switching and adaptation. ConclusionWe are evaluating BET + BRAF + EGFR inhibition in patients with treatment-refractory BRAFV600E metastatic CRC. ClinicalTrial.gov identifier: NCT06102902. What is already known on this topicEnhancer aberrations emerge as critical epigenetic features in the progression of colorectal cancer (CRC). However, the dynamics of active enhancer and the therapeutic potential of enhancer blockade, particularly in CRC tumors with BRAFV600E mutation, is not well understood. What this study addsThis study demonstrates improved efficacy of BET inhibitor combination therapies in diverse patient-derived models and reveals epigenetic reprogramming driven cellular plasticity in BRAFV600E-mutated CRC. How this study might affect research, practice or policyOur findings support treatment with BET + BRAF + EGFR inhibitors for patients with BRAFV600E-mutant mCRC [NCT06102902]. This study also highlights the potential of combining epigenetic agents to standard targeted therapy, offering a novel treatment option for this subset of patients.

cancer biology↗

bioRxiv2025

Brain Network Analysis in Alzheimer's Disease and Mild Cognitive Impairment using High-Density Diffuse Optical Tomography

Dementia is associated with altered resting state connectivity, measures of which could aid in its early detection and monitoring. High-density diffuse optical tomography (HD-DOT) is well-suited to detect these alterations at scale due to its numerous practical advantages, but it has not yet been applied to dementia. In this study, we investigated resting state functional connectivity across the prefrontal cortex in individuals with Mild Cognitive Impairment (MCI, n = 22), Alzheimers Disease (AD, n = 21), and in healthy controls (n = 22). A graph theoretical approach was taken to characterise both global and local patterns of connectivity over a five-minute resting period. We found that individuals with AD and MCI exhibited denser and stronger networks, with shorter path lengths, as well as a loss of consistent key network hubs with worsening cognitive impairment. These results indicate that networks in dementia are more globally connected, albeit in a disorganised manner, perhaps reflecting the recruitment of additional connections for short-term stability which may be ultimately damaging in the long-term. Following the demonstration of HD-DOTs capacity to detect differences between healthy ageing and dementia, this work opens up new possibilities for the use of optical imaging in the study of this clinical population and HD-DOTs potential for scalable clinical use.

neuroscience↗

bioRxiv2025

In vitro model of human subcutaneous adipocyte spheroids for studying mitochondrial dysfunction and mitochondria activating compounds

Mitochondrial abnormalities drive subcutaneous white adipose tissue dysfunction in obesity, leading to metabolic complications. A key challenge in obesity research is the lack of in vitro models to study human adipocyte mitochondria. Here, we establish a human subcutaneous adipocyte spheroid model to characterize mitochondrial metabolism under obesity-relevant conditions and drug exposure. Human preadipocyte spheroids were differentiated in ultra-low attachment plates for 3 weeks in media free of thiazolidinediones. The differentiated adipocyte spheroids showed increased lipid accumulation, adipogenic gene expression, mitochondrial respiration and adiponectin secretion, and a proper response to hormonal stimulation. Lipid mixture administration during differentiation induced metabolic disturbances including mitochondrial respiration failure associated with increased mitochondrial biogenesis. Post-differentiation treatment with rosiglitazone, a peroxisome proliferator-activated receptor {gamma} agonist, improved mitochondrial bioenergetics and adiponectin secretion in lipid mixture-administered adipocyte spheroids. Our model enables precise measurement of adipocyte mitochondria under various conditions, providing a platform for mitochondria-related research and drug discovery in obesity.

molecular biology↗

bioRxiv2025

EcDNA-borne PVT1 fusion stabilizes oncogenic mRNAs

Extrachromosomal DNA (ecDNA) amplifications are prevalent drivers of human cancers. We show that ecDNAs exhibit elevated structural variants leading to gene fusions that produce oncogene fusion transcripts. The long noncoding RNA (lncRNA) gene PVT1 is the most recurrent structural variant across cancer genomes, with PVT1-MYC fusions arising most frequently on ecDNA. PVT1 exon 1 is the predominant 5 partner fused to MYC or other oncogenes on the 3 end. Mechanistic studies demonstrate that PVT1 exon 1 confers enhanced RNA stability for fusion transcripts, which requires PVT1 exon 1 interaction with SRSF1 protein. Genetic rescue of MYC-addicted cancer models and isoform-specific single-cell RNA sequencing of tumors reveal that PVT1-MYC better supports MYC dependency and better activates MYC target genes in vivo. Thus, the mutagenic landscape of ecDNA contributes to genome instability and generates chimeric fusions of lncRNA and mRNA genes, selecting PVT1 5 region as a stabilizer of oncogene mRNAs.

cancer biology↗

bioRxiv2025

Decoupling Phase Separation and Fibrillization Preserves Activity of Biomolecular Condensates

Age-dependent transition of metastable, liquid-like protein condensates to amyloid fibrils is an emergent phenomenon of numerous neurodegeneration-linked protein systems. A key question is whether the thermodynamic driving forces underlying reversible phase separation and maturation to irreversible amyloids are distinct and separable. Here, we address this question using an engineered version of the microtubule-associated protein Tau, which forms biochemically active condensates. Liquid-like Tau condensates exhibit rapid aging to amyloid fibrils under quiescent, cofactor-free conditions. In particular, the Tau condensate interface promotes fibril nucleation, thereby impairing condensate activity in recruiting tubulin and catalyzing microtubule assembly. Remarkably, a small molecule metabolite, L-arginine, selectively impedes condensate-to-fibril transition without perturbing phase separation in a valence and chemistry-specific manner. By enhancing condensate viscoelasticity, L-arginine counteracts age-dependent decline in the biochemical activity of Tau condensates. These results provide a proof-of-principle demonstration that small molecule metabolites can reinforce the metastability of protein condensates against a liquid-to-amyloid transition, thereby preserving condensate function.

biophysics↗

bioRxiv2025

Miniaturized Workflow for Transcriptomic Profiling of Urinary Extracellular RNA during Pregnancy

Urine contains extracellular RNA (exRNA) carried by extracellular vesicles (EVs) and other biomolecular complexes. There is currently a need for studies focused on female cohorts to develop new methods for non-invasive analysis of biofluids to create reference profiles and for identification of biomarkers of reproductive and pregnancy disorders. The objective of this study was therefore to identify optimal methods for transcriptomic profiling of urine by testing different exRNA isolation and scalable library preparation methods that enable detection of biomarkers that reflect pregnancy-associated changes in the placenta and maternal tissues. RNA was extracted from pooled and individual urine samples obtained from normal non-pregnant and pregnant females, as well as males, using input volumes of either 0.6 mL, 1 mL, or 4 mL. Samples were extracted using methods that focused either on isolating vesicular (EV-associated) or total (EV-associated and non EV-associated) exRNA. Small RNA libraries (n=208) were prepared using the NEBNext Small RNA Library Prep kit and long RNA libraries (n=97) were prepared using the SMART-Seq v4 Ultra Low Input RNA or the SMARTer Stranded Total RNA-Seq Kit v2 Pico Input kits (Takara). Principal component analysis showed that the greatest source of variance amongst technical replicates of small RNA libraries (n=176 which passed quality control) was exRNA isolation method, and amongst long RNA libraries (n=97 which passed quality control) was library preparation method. Long RNA libraries prepared from exRNA extracted using miRCURY showed that the SMART-Seq v4 method yielded significantly more uniquely mapped reads compared to the Pico v2 method (p<0.05). We have established a scalable pipeline for small and long RNA-Seq profiling of exRNA in urine in a reproducible manner, which we used to identify differentially expressed urinary exRNAs in pregnancy, and will enable transcriptomic profiling of urinary exRNA in disorders of pregnancy, including preeclampsia.

genetics↗

bioRxiv2025

Tracing the function expansion for a primordial protein fold in the era of fold-based function prediction: beta-trefoil

The incredibly narrow protein fold bottleneck, which separates the billions of unique proteins on one side to deliver diverse biological functions on the other, arises from folds that tolerate mutations during evolution. One such fold, called the {beta}-trefoil, is present in functionally diverse proteins including cytokines involved in the immune system such as interleukin-1. The unrecognizable sequence-level diversity, even among paralogs of interleukin-1 within the same chromosomal locus, suggests the resilience of this fold to mutational onslaught. Furthermore, {beta}-trefoil domain containing-proteins are known to coexist with other domains to achieve functional diversity. In this study, we challenge the reach and limitations of function prediction using fold-fold comparison using {beta}-trefoil fold as an example. We identified proteins containing {beta}-trefoil fold belonging to thirty-two distinct functional class based on diverse domain architecture and or functional annotation by mining both the PDB and AlphaFold databases using fold-fold comparison. Among the proteins with novel domain architecture we find {beta}-trefoil along with chitinase, lipase, {beta}-glucosidase, protein kinase, peptidoglycan-binding + peptidase matrixin, glycosyl hydrolases family 3 + PA14 + fibronectin type-III, alpha galactosidase A, PhoD-like phosphatase, insecticidal crystal toxin, trypsin, alginate lyase and two novel structurally uncharacterized domains. We demonstrate that fold-fold comparison can extend function prediction beyond the reach of sequence-based approach and provides an opportunity to discover novel domain architecture associated with known folds. However, since extending fold similarity to functional similarity may be challenged by convergent fold evolution, we explore if {beta}-trefoil may be a convergent evolution and share our hypothesis.

bioinformatics↗

bioRxiv2025

A Syntenic Pangenome for Gardnerella Reveals Taxonomic Boundaries and Stratification of Metabolic and Virulence Potential across Species

Gardnerella species are central to bacterial vaginosis (BV), a condition affecting nearly one in three women of reproductive age and associated with preterm birth and increased susceptibility to sexually transmitted infections. Despite decades of study, progress in defining Gardnerella diversity has been hindered by inconsistent taxonomy and poor-quality genomic resources. Here, we sequenced 392 new Gardnerella isolates from asymptomatic and BV-associated microbiota and integrated this collection with all publicly available genomes. After stringent curation, we generated a high-quality reference set of 313 distinct genomes that underpins a comprehensive taxonomic framework. Using average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), and phylogenomics, we resolved 21 genomic lineages encompassing 11 species and 15 subspecies, each assigned a provisional formal name. Integration of complete long-read assemblies enabled construction of the first syntenic Gardnerella pangenome, revealing lineage-specific repertoires of virulence, metabolic, and defense systems - including variable sialidases (NanH), vaginolysin, and amino-acid biosynthetic pathways - and defining conserved genomic architecture across species. Comparative methylome profiling further highlighted restriction-modification system diversity that may influence genetic exchange. Finally, we identified the first native cryptic plasmids in Gardnerella, overturning the assumption that the genus lacks plasmids, and demonstrated their use in generating a replicative E. coli-Gardnerella shuttle vector. Together, these results establish a complete genomic and functional framework for Gardnerella, providing a reproducible foundation for mechanistic and translational studies of BV and a model for resolving taxonomy and functional stratification in other urogenital-associated bacteria.

microbiology↗