Biology subjects

Jiang, H.

Publications and source records attributed to Jiang, H..

At least 109 records · Page 6Linked to original sources

bioRxiv2025

A novel enterococcus phage endolysin Lys22 with a wide host range against mixed biofilm of Enterococcus faecalis, Staphylococcus aureus and Acinetobacter baumannii

The global surge in multidrug-resistant (MDR) bacterial pathogens has created an urgent imperative for innovative antimicrobial strategies. Enterococcus faecalis, Staphylococcus aureus, and Acinetobacter baumannii demonstrate remarkable antibiotic resistance and dominate hospital-acquired infections. These bacteria often form biofilms, a complex community structure that shields them from immune system phagocytosis, resists antibiotic penetration, and enhances their survival in harsh environments. In clinical cases, these bacteria often form mixed biofilms and lead to treatment failures. Phages and their derivatives have emerged as promising candidates in the fight against drug-resistant bacteria. Lys22, an endolysin derived from an enterococcus phage, has been cloned and demonstrated to possess a broad host range, effectively targeting E. faecalis, various Staphylococcus species, and A. baumannii. When applied to the biofilms formed by these bacteria, Lys22 was found to significantly inhibit both simple and complex biofilms in vitro. Virulent genes, including agrA, sarA, and icaA in S. aureus; asa1, cylA, and hyl in E. faecalis; and OmpA and lpsB in A. baumannii were also downregulated by Lys22. Notably, Lys22 also exhibited a robust protective effect against dual or triple infections involving E. faecalis, S. aureus, and A. baumannii in a zebrafish eggs model, highlighting its potential as a therapeutic agent in combatting multi-bacterial infections.

microbiology↗

bioRxiv2025

MCMC-CE: A Novel and Efficient Algorithm for Estimating Small Right-Tail Probabilities of Quadratic Forms with Applications in Genomics

Quadratic forms of multivariate normal variables play a critical role in statistical applications, particularly in genomics and bioinformatics. However, accurately computing small right-tail probabilities (p-values) for large-scale quadratic forms is computationally challenging due to the intractability of their probability distributions, as well as significant numerical constraints and computational burdens. To address these problems, we propose MCMC-CE, an innovative algorithm that integrates Markov Chain Monte Carlo (MCMC) sampling with the cross-entropy (CE) method, coupled with leading-eigenvalue extraction and Satterthwaite-type approximation techniques. Our approach efficiently estimates small p-values for quadratic forms with their ranks exceeding 10,000. Through extensive simulation studies and real-world applications in genomics, including genome-wide association studies and pathway enrichment analyses, our method demonstrates advantageous numerical accuracy and computational reliability compared to existing approaches such as Davies, Imhofs, Farebrothers, Liu-Tang-Zhangs and saddlepoint approximation methods. MCMC-CE provides a robust and scalable solution for accurately computing small p-values for quadratic forms, facilitating more precise statistical inference in large-scale genomic studies.

bioinformatics↗

bioRxiv2025

Nucleosome binding relinquishes the association of the BAH domain of Orc1 with Sir1

Mating-type switching in S. cerevisiae requires silencing of the homothallic mating (HM) loci through formation of position-dependent, gene-independent repressive chromatin domains, resembling heterochromatic regions in higher eukaryotes. Genetic and biochemical studies have identified cis-acting DNA elements, called silencers, and trans-acting protein factors important for the establishment and maintenance of the silent chromatin. Yet, the molecular mechanism governing the position-dependence of gene silencing is not fully understood. Here we report that the BAH domain of Orc1, which is responsible for recruiting Sir1 to the Orc1-bound silencers, ceases to bind Sir1 in the presence of nucleosome. This finding suggests a unified role of sensing the chromatin environment by Orc1s BAH domain in transcriptional silencing and specification of replication origins. We further dissected the structural determinants of the BAH domain required for binding Sir1. These results expanded the understanding of Orc1s functions in epigenetic silencing of the HM loci.

molecular biology↗

bioRxiv2025

Ultrasonic Modulation of Astrocytic and Neuronal Calcium Dynamics in Mouse Cortex

BackgroundAstrocytes are abundant in the brain and their calcium signaling is reported to have an important effect on neuronal activity in both physiological and pathological conditions. Low-frequency focused ultrasound (FUS) has recently emerged as a powerful noninvasive neuromodulation approach, yet its impact on astrocyte calcium dynamics in different brain states in vivo is poorly understood. ObjectiveThis study aimed to elucidate the effects of non-thermal FUS on astrocyte calcium dynamic with in vivo cellular-resolution and cell-type-specific recording and identify whether the influences of FUS on cortical astrocytes and neurons are distinctive and state dependent. MethodsHere we combined a customized 0.521MHz FUS transducer with two-photon microscopy, allowing simultaneous single-cell resoultion imaging and FUS stimulation at intensities of 0.91 or 1.5 W/cm2 to examine astrocyte and neuronal calcium responses in somatosensory cortex of both awake and lightly anesthetized mice. Functional clustering analysis was performed to identify calcium response activated or inhibited subpopulations. ResultsIn awake mice, FUS significantly enhanced the amplitude, frequency, and temporal integral of astrocyte calcium transients, while suppressing neuronal calcium activity and reducing the proportion of activated neuronal subpopulations. In contrast, lightly anesthetized mice displayed a blunted yet increased astrocyte response and negligible neuronal modulation under FUS, suggesting that baseline suppression from anesthesia partially masks FUS effects. ConclusionsOur study demonstrated that FUS elicited distinctive, state-dependent effects on cortical astrocytes and neurons, highlighting astrocytes as previously underappreciated targets of ultrasound neuromodulation. These findings will pave the way for FUS-based therapies targeting astrocyte-neuron interactions in conditions involving abnormal brain excitability. HighlightsO_LILow duty cycle low frequency focused ultrasound induced negligible heat effects. C_LIO_LIUltrasound markedly enhanced astrocyte calcium transients in awake mice. C_LIO_LIUltrasound suppressed neuronal calcium activity in awake mice. C_LIO_LIThe effects of ultrasound on both cell types were reduced under light anesthesia. C_LI

bioengineering↗

bioRxiv2025

Environmental microbiomes drive chemotactile sensation in octopus

Microbial communities coat nearly every surface in the environment and have co-existed with animals throughout evolution. Whether animals exploit omnipresent microbial cues to navigate their surroundings is not well understood. Octopuses use "taste by touch" chemotactile receptors (CRs) to explore the seafloor, but how they distinguish meaningful surfaces from the rocks and crevices they encounter is unknown. Here, we report that secreted signals from microbiomes of ecologically relevant surfaces activate CRs to guide octopus behavior. Distinct molecules isolated from specific bacterial strains located on prey or eggs bind single CRs in subtly different structural conformations to elicit distinct mechanisms of receptor activation, ion permeation and signal transduction, and maternal care and predation behavior. Thus, microbiomes on ecological surfaces act at the level of primary sensory receptors to inform behavior. Our study demonstrates that uncovering interkingdom interactions is essential to understanding how animal sensory systems evolved in a microbe rich world. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/641191v1_ufig1.gif" ALT="Figure 1"> View larger version (140K): org.highwire.dtl.DTLVardef@15f365eorg.highwire.dtl.DTLVardef@1ea5606org.highwire.dtl.DTLVardef@1b5ad1aorg.highwire.dtl.DTLVardef@779e6e_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIChemotactile receptors (CRs) detect microbiomes of prey and progeny C_LIO_LIDiverse microbial signals bind single CRs with distinct structural conformations C_LIO_LIDistinct microbial signals activate single CRs to permeate different ions C_LIO_LIEnvironmental microbes elicit octopus predatory and maternal behaviors C_LI

physiology↗

bioRxiv2025

Mesoderm-specific transcript reduces ciliary sphingomyelin levels to promote tendon stem/progenitor cells osteochondrogenesis in traumatic heterotopic ossification

Traumatic heterotopic ossification (tHO) is a musculoskeletal disorder characterized by ectopic bone formation in soft tissues following trauma. However, the etiology and mechanisms of tHO remain unknown, and no treatments are highly effective for tHO. Here, by performing single-cell RNA sequencing (scRNA-seq) on two tHO mouse models, we found that ciliary Hedgehog (Hh) and PI3K-Akt signaling in tendon stem/progenitor cells (TSPCs) is upregulated during tHO development, leading to the activation of GLI family zinc finger 2 (GLI2) transcription factor, which promotes mesoderm-specific transcript (MEST) gene expression. Untargeted lipidomics using liquid chromatography-tandem mass spectrometry (LC-MS/MS) on detached cilia indicated that MEST could reduce ciliary sphingomyelin (SM) levels by inhibiting SM synthesis in TSPCs, creating a positive feedback loop that amplified ciliary Hh signaling, enhancing TSPCs osteochondrogenesis and driving tHO formation. Targeting ciliary genes intraflagellar transport 88 (IFT88) or ADP ribosylation factor like GTPase 3 (ARL3) restored normal TSPCs osteochondrogenesis in vitro and attenuated ectopic bone formation in vivo by suppressing Hh and PI3K-Akt signaling. AAV-mediated MEST inhibition or exogenous SM administration in vivo also alleviates tHO progression. These findings may provide novel insights into tHO pathogenesis and potential therapeutic strategies.

molecular biology↗

bioRxiv2025

Small-molecule screen in C. elegans identifies benzenesulfonamides as inhibitors of microsporidia spores

Microsporidia, a large group of fungal-related intracellular parasites, infect several economically significant animals, leading to substantial economic losses. As currently available anti-microsporidia therapies are either ineffective or come with numerous adverse effects, there is a need for alternative microsporidia inhibitors. Here we screen a subset of the ChemBridge DIVERset library, comprising 2500 diverse compounds, using Caenorhabditis elegans infected with its natural microsporidian parasite, Nematocida parisii. By testing these compounds at 60 M in 96-well assay plates, we identified 26 hits that restored the ability of C. elegans to produce progeny in the presence of N. parisii. We confirmed that out of 20 tested compounds, 18 ChemBridge compounds effectively inhibit N. parisii infection in C. elegans. Of these 18, 10 were benzenesulfonamide derivatives which inhibit microsporidia infection by inactivating spores. We screened an additional 475-compound benzenesulfonamide library, successfully identifying three compounds that are effective at a lower concentration than the initial hits. We further show that one benzenesulfonamide compound displays inhibitory activity against several species of microsporidia, inhibiting infection of species belonging to the Nematocida, Enterocytozoon, and Encephalitozoon genera. Together our results suggest that benzenesulfonamides are a potential scaffold for the development of microsporidia antiseptics.

microbiology↗

bioRxiv2025

China Autism Brain Imaging Consortium: Charting Brain Growth in Chinese Children with Autism

Autism Spectrum Disorder (ASD) is a lifelong neurodevelopmental condition characterized by atypical brain growth. While advances in neuroimaging and openly sharing large-sample datasets such as the Autism Brain Imaging Data Exchange (ABIDE) have improved understanding of ASD, most studies focus on adolescents and adults, with early brain development-critical for diagnosis and intervention-remaining underexplored. Existing research predominantly involves Western samples, offering limited insight and generalizability into non-Caucasian populations. We introduce the China Autism Brain Imaging Consortium (CABIC) (https://php.bdnilab.com/resources/), a grassroots effort by researchers across the country to aggregate previously collected multi-site structural MRI datasets and phenotypic information from 1,451 autistic children and 1,119 typically developing children, covering an age range from early childhood to school age (1.0 - 12.92 years). Here, we present this resource and depict brain growth charts to push forward a more comprehensive understanding of the brain development in Chinese autism children. We constructed brain growth charts that reveal a developmental shift in autistic children, transitioning from early overgrowth to delayed maturation. Regional analyses identified distinct atypical trajectories across specific brain regions. Individual deviation scores quantified inter-subject variability, characterizing the heterogeneity of brain development in ASD. Comparative analyses between CABIC and ABIDE highlighted differences potentially attributable to ethnicity and culture, advancing our understanding of cross-population neurodevelopmental diversity. CABIC MRI datasets will be shared publicly to foster investigation of the potential neural mechanisms underlying ASD in non-Western populations and support efforts toward precision medicine for autistic individuals across diverse backgrounds.

neuroscience↗

bioRxiv2025

Ultradeep N-glycoproteome Atlas of Mouse Reveals Spatiotemporal Signatures of Brain Aging and Neurodegenerative Diseases

The current depth of site-specific N-glycoproteomics is insufficient to fully characterize glycosylation events in biological samples. Herein, we achieved an ultradeep and precision analysis of the N-glycoproteome of mouse tissues by integrating multiple workflows. The largest N-glycoproteomic dataset to date was established on mice, which contained 91,972 precursor glycopeptides, 62,216 glycoforms, 8,939 glycosites and 4,563 glycoproteins. The database consisted of 6.8 million glyco-spectra (containing oxonium ions), among which 160,928 were high-quality spectra with confident N-glycopeptide identifications. The large-scale and high-quality dataset enhanced the performance of current artificial intelligence models for glycopeptide tandem spectrum prediction. Using this ultradeep dataset, we observed tissue specific microheterogeneity and functional implications of protein glycosylation in mice. Furthermore, the region-resolved brain N-glycoproteomes for Alzheimers Diseases, Parkinson Disease and aging mice revealed the spatiotemporal signatures and distinct pathological functions of the N-glycoproteins. A comprehensive database resource of experimental N-glycoproteomic data from this study and previous literatures were further established. This N-glycoproteome atlas serves as a promising tool for revealing the role of protein glycosylation in biological systems.

neuroscience↗

bioRxiv2025

Uridine Metabolism as a Targetable Metabolic Achilles' Heel for chemo-resistant B-ALL

Relapse continues to limit survival for patients with B-cell acute lymphoblastic leukemia (B-ALL). Previous studies have independently implicated activation of B-cell developmental signaling pathways and increased glucose consumption with chemo-resistance and relapse risk. Here, we connect these observations, demonstrating that B-ALL cells with active signaling, defined by high expression of phosphorylated ribosomal protein S6 ("pS6+ cells"), are metabolically unique and glucose dependent. Isotope tracing and metabolic flux analysis confirm that pS6+ cells are highly glycolytic and notably sensitive to glucose deprivation, relying on glucose for de novo nucleotide synthesis. Uridine, but not purine or pyrimidine, rescues pS6+ cells from glucose deprivation, highlighting uridine is essential for their survival. Active signaling in pS6+ cells drives uridine production through activating phosphorylation of carbamoyl phosphate synthetase (CAD), the enzyme catalyzing the initial steps of uridine synthesis. Inhibition of signaling abolishes glucose dependency and CAD phosphorylation in pS6+ cells. Primary pS6+ cells demonstrate high expression of uridine synthesis proteins, including dihydroorotate dehydrogenase (DHODH), the rate-limiting catalyst of de novo uridine synthesis. Gene expression demonstrates that increased expression of DHODH is associated with relapse and inferior event-free survival after chemotherapy. Further, the majority of B-ALL genomic subtypes demonstrate activity of DHODH. Inhibiting DHODH using BAY2402232 effectively kills pS6+ cells in vitro, with its IC50 correlated with the strength of pS6 signaling across 14 B-ALL cell lines and patient-derived xenografts (PDX). In vivo DHODH inhibition prolongs survival and decreases leukemia burden in pS6+ B-ALL cell line and PDX models. These findings link active signaling to uridine dependency in B-ALL cells and an associated risk of relapse. Targeting uridine synthesis through DHODH inhibition offers a promising therapeutic strategy for chemo-resistant B-ALL as a novel therapeutic approach for resistant disease.

cancer biology↗

bioRxiv2025

Decoding human placental cellular and molecular responses to maternal obesity and fetal growth

Maternal obesity increases risk of large-for-gestational-age (LGA) births and subsequent cardiometabolic disorders in offspring. To identify placental signatures associated with these outcomes, we performed single-nucleus RNAseq on placentas from women with obesity delivering appropriate-for-gestational-age (AGA) or LGA infants, compared to normal-weight controls. In maternal obesity, regardless of fetal growth, syncytiotrophoblasts showed upregulated hypoxia and TNF- signaling, while cytotrophoblasts exhibited downregulated receptor tyrosine kinase signaling. However, only in LGA placentas, villous non-trophoblasts displayed upregulated TNF- signaling and inflammatory responses. Notably, Hofbauer cells in LGA placentas presented transcriptional alterations in immunometabolism-related genes and functioned as main signaling senders via SPP1. Importantly, we recapitulated syncytiotrophoblast responses to maternal obesity using a novel microfluidic organoids-on-a-chip co-culture. These findings reveal distinct transcriptional responses of placental cell types to maternal obesity and fetal growth, highlighting potential intervention pathways to mitigate future disease risks.

developmental biology↗

bioRxiv2025

IL-9 as a naturally orthogonal cytokine with optimal JAK/STAT signaling for engineered T cell therapy

Arming T cells with a synthetically orthogonal IL-9 receptor (o9R) permits facile engraftment and potent anti-tumor functions. We considered whether the paucity of natural IL-9R expression could be exploited for T cell immunotherapy given that, in mice, high doses of IL-9 were well-tolerated without discernible immune modulation. Compared to o9R, T cells engineered with IL-9R exhibit superior tissue infiltration, stemness, and anti-tumor activity. These qualities are consistent with a stronger JAK/STAT signal, which in addition to STAT1/3/5, unexpectedly includes STAT4 (canonically associated with IL-12 but not common {gamma}-chain cytokines). IL-9R T cells are exquisitely sensitive to perturbations of proximal signaling, including structure-guided attenuation, amplification, and rebalancing of JAK/STAT signals. Biased IL-9R mutants uncover STAT1 as a rheostat between proliferative stem-like and terminally differentiated effector states. In summary, we identify native IL-9/IL-9R as a natural cytokine-receptor pair with near-orthogonal qualities and an optimal JAK/STAT signaling profile for engineered T cell therapy.

immunology↗

bioRxiv2025

Structural Basis for the Assembly of Amyloid Fibrils by the Master Cell-Signaling Regulator Human Receptor-Interacting Protein Kinase 1

Amyloid fibrils, typically associated with neurodegenerative diseases, also play critical roles as functional assemblies in biological processes. The RIP homotypic interaction motifs (RHIMs) in receptor-interacting protein kinases 1 and 3 (RIPK1 and RIPK3) are essential for necroptosis, orchestrating the formation of amyloid-like fibrils that assemble into necrosomes. These supramolecular complexes propagate cell death signals and activate effectors like MLKL. While the structures of human RIPK3 (hRIPK3) homomeric fibrils and RIPK1-RIPK3 heteromeric fibrils have been resolved, the atomic structure of human RIPK1 (hRIPK1) homomeric fibrils has remained elusive. Here, we present a high-resolution structure of hRIPK1 RHIM-mediated amyloid fibrils, determined using an integrative approach combining cryoprobe-detected solid-state nuclear magnetic resonance spectroscopy and cryo-electron microscopy. The fibrils adopt an N-shaped amyloid fold consisting of three {beta}-sheets stabilized by the conserved IQIG RHIM motif through hydrophobic interactions and hydrogen bonding. A key hydrogen bond between N545 and G542 closes the {beta}2-{beta}3 loop, resulting in denser side-chain packing compared to hRIPK3 homomeric fibrils. This structural feature likely contributes to the compact architecture of hRIPK1 fibrils, in contrast to the more relaxed S-shaped fold observed in hRIPK3. These findings provide structural insights into how hRIPK1 homomeric fibrils nucleate hRIPK3 recruitment and fibrillization during necroptosis, offering broader perspectives on the molecular principles governing RHIM-mediated amyloid assembly and functional amyloids.

biophysics↗

bioRxiv2025

Rational Design and Optimization of a Potent IDO1 Proteolysis Targeting Chimera (PROTAC)

Indoleamine 2,3-dioxygenase 1 (IDO1) is a potently immunosuppressive protein that inhibits antitumor immunity through both tryptophan metabolism and non-enzymatic functions. Pharmacological therapies targeting IDO1 enzyme activity have generally failed to improve the overall survival of patients with cancer. Developing new therapeutic agents that are capable of neutralizing both enzyme-and non-enzyme-derived immunosuppressive IDO1 effects is therefore of high interest. We previously described the development of a novel Proteolysis Targeting Chimera (PROTAC), NU223612, that degrades IDO1 in cultured human glioblastoma (GBM) cells, as well as in well-established brain tumors, in vivo. In this study, we rationally optimized the composition, rigidity, and linker orientation of the PROTAC structure to create NU227326, which degrades IDO1 with a DC50 of 5 nM in human GBM cells. Mechanistic studies showed that IDO1 degradation occurred through the ubiquitin-proteasome system and was sustained for at least 2 days, supporting NU227326 as a highly potent IDO1 PROTAC suitable for further studies in GBM and other human cancers.

biochemistry↗

bioRxiv2024

Exploring Genetic Interactions with Rare Variants Reveals Gene Networks Susceptible to Complex Diseases

Genetic interactions play a crucial role in understanding the susceptibility and etiology of complex human diseases. However, existing methods for analyzing gene-gene interactions are often limited to common variants and may not capture the effects of rare variants. In this study, we propose a novel method called GGI-RUNNER that is specifically designed for analyzing gene-gene interactions of rare variants. GGI-RUNNER evaluates the enrichment of rare variant interaction burden in patients relative to baselines in the general population. The baselines are estimated for pairwise genes by a recursive truncated negative-binomial regression model on multiple genomic features available from public data. Intensive simulations demonstrate that GGI-RUNNER exhibits substantially higher statistical power than alternative epistasis tests and maintains reasonable type I error rates even in stratified populations. Applied to real data, GGI-RUNNER identified significant rare variant interactions associated with Alzheimers disease, Hirschsprungs disease, Ulcerative colitis and Crohns disease. Furthermore, we found that these identified genes for each trait can form interconnected networks, which may provide valuable insights into the underlying molecular mechanisms.

bioinformatics↗

bioRxiv2024

An immunomechanical checkpoint PYK2 governs monocyte-to-macrophage differentiation in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a fibrotic, stiff tumor microenvironment (TME), where tumor-associated macrophages (TAMs) drive ECM remodeling, progression, and immune evasion. The contribution of mechanical cues to monocyte differentiation into TAMs remains largely unexplored. Here we show that mechanical force is required for monocyte-to-macrophage differentiation. PYK2, as an innovative immunomechanical checkpoint, de facto governs this differentiation process. We demonstrated that PYK2 senses mechanical signals via Piezo1 and integrins, triggering F-actin polymerization and translocating to the nucleus to regulate mechanotransduction and differentiation genes (e.g., ACTR3, RELA). Targeted deletion of PYK2 impairs the differentiation and polarization of monocyte-derived macrophages, reshapes the PDAC microenvironment, and enhances the efficacy of anti-PD-1 immunotherapy. These findings underscore the critical role of mechanical cues in monocyte differentiation and suggest that targeting PYK2 is a promising strategy to modulate TAM function and improve immunotherapy outcomes in patients with PDAC. Statement of significanceThis study identifies PYK2 as an immunomechanical checkpoint that drives monocyte-to-macrophage differentiation in PDAC via Piezo1/integrin-mediated mechanical cues. Targeted deletion of PYK2 reshapes the PDAC microenvironment, and enhances the efficacy of anti-PD-1 immunotherapy, suggesting PYK2 as a promising therapeutic target to overcome immunotherapy resistance.

immunology↗

bioRxiv2024

Targeted detection of endogenous LINE-1 proteins and ORF2p interactions

BackgroundBoth the expression and activities of LINE-1 (L1) retrotransposons are known to occur in numerous cell-types and are implicated in pathobiological contexts such as aging-related inflammation, autoimmunity, and in cancers. L1s encode two proteins that are translated from bicistronic transcripts. The translation product of ORF1 (ORF1p) has been robustly detected by immunoassays and shotgun mass spectrometry (MS). Yet, more sensitive detection methods would enhance the use of ORF1p as a clinical biomarker. In contrast, until now, no direct evidence of endogenous L1 ORF2 translation to protein (ORF2p) has been shown. Instead, assays for ORF2p have been limited to ectopic L1 ORF over-expression contexts and to indirect detection of endogenous ORF2p enzymatic activity, such as by the sequencing of de novo genomic insertions. Immunoassays for endogenous ORF2p have been problematic, producing apparent false positives due to cross-reactivities, and shotgun MS has not yielded reliable evidence of ORF2p peptides in biological samples. ResultsHere we present targeted mass spectrometry assays, selected and parallel reaction monitoring (SRM and PRM, respectively) to detect and quantify L1 ORF1p and ORF2p at their endogenous abundances. We were able to quantify ORF1p and ORF2p present in our samples down to a range in the low attomoles. Confident in our ability to affinity enrich ORF2p, we describe an interactome associated with endogenous ORF2-containing macromolecular assemblies. ConclusionThis is the first assay to demonstrate sensitive and robust quantitation of endogenous ORF2p. The ability to assay ORF2p directly and quantitatively will improve our understanding of the developmental and diseased cell states where L1 expression and its activity naturally occur. The ability to simultaneously assay endogenous L1 ORF1p and ORF2p is an important step forward for L1 analytical biochemistry. Endogenous ORF2p interactomes can now be presented with confidence that ORF2p is among the enriched proteins.

molecular biology↗

bioRxiv2024

Identification of the MRTFA/SRF pathway as a critical regulator of quiescence in cancer.

Chemoresistance is a major driver of cancer deaths. One understudied mechanism of chemoresistance is quiescence. We used single cell culture to identify, retrieve, and RNA-Seq profile primary quiescent ovarian cancer cells (qOvCa). We found that many qOvCa differentially expressed genes are transcriptional targets of the Myocardin Related Transcription Factor/Serum Response Factor (MRTF/SRF) pathway. We also found that genetic disruption of MRTF-SRF interaction, or an MRTF/SRF inhibitor (CCG257081) impact qOvCa gene expression and induce a quiescent state in cancer cells. Suggesting a broad role for this pathway in quiescence, CCG257081 treatment induced quiescence in breast, lung, colon, pancreatic and ovarian cancer cells. Furthermore, CCG081 (i) maintained a quiescent state in patient derived breast cancer organoids and, (ii) induced tumor growth arrest in ovarian cancer xenografts. Together, these data suggest that MRTF/SRF pathway is a critical regulator of quiescence in cancer and a possible therapeutic target. SignificanceQuiescence is a critical driver of chemoresistance. The MRFT-SRF pathway regulates cancer cell quiescence and inhibiting the MRTF-SRF pathway can prevent the outgrowth of quiescent cancer cells and improve cancer outcomes.

cancer biology↗