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Protein & Cell

◐ Oxford University Press (OUP)

Preprints posted in the last 90 days, ranked by how well they match Protein & Cell's content profile, based on 25 papers previously published here. The average preprint has a 0.02% match score for this journal, so anything above that is already an above-average fit.

1
Identification of Novel Inhibitors of JEV RdRp as Potent Antiviral Drugs: Targeting NS5-NS3 Protein Interaction

Mishra, P.; Mishra, S.; Srivastava, G.; Archana, K.; Siddiqi, M. I.; Haldar, S.; Tripathi, R. K.

2026-09-28 pathology 10.64898/2026.09.23.753689 medRxiv
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Japanese Encephalitis Virus (JEV) belongs to the Flavivirus family, and the RNA dependent RNA polymerase (RdRp) domain located at the C terminus of non structural protein 5 (NS5) regulates de novo viral genome synthesis. The conserved priming loop inserted in the thumb domain of RDRP initiates de novo genome synthesis. Interestingly, the reported replication process initiates with an interaction between NS5 (methyltransferase/RDRP) and NS3 (protease/helicase), and inhibiting this interaction directly correlates with the inhibition of viral replication. The function of the priming loop in the context of the NS5 NS3 interaction is not yet known. In this study, we studied the priming loop function in the NS5 NS3 interaction and viral replication. Using a structure based drug design approach, we screened the Maybridge compound library against the RdRp priming loop and identified 15 candidate compounds based on binding energy. Among them, DSHS00151 showed significant dose dependent inhibition of the NS5 NS3 interaction with an IC50 of 3.5 micromolar in the mammalian two hybrid assay, inhibited viral infectivity with an IC50 of 2.54 micromolar, and reduced viral RNA load with an IC50 of 2.9 micromolar, compared to CD10712. Molecular Dynamics (MD) simulations revealed that DSHS00151 exhibits stronger and more stable binding with the priming loop residues (790 to 812) compared to CD10712. The molecular mechanism suggested by the docking of the NS5 and NS3 proteins showed that the priming loop tends to rotate toward the NS3 protein to stabilize the complex, and compound binding restricts this loop rotation, thus compromising the stability of the NS5 and NS3 complex and affecting viral replication. Overall, our study validated the function of the NS5 priming loop as an allosteric site, and compounds binding to this allosteric site belong to the Non Nucleoside Reverse Transcriptase Inhibitors (NNRTI) class of inhibitors, which disrupt the NS5 and NS3 interaction and could be developed as novel anti JEV therapeutics.

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CRISPR-FOIL: A Programmable CRISPR Tool to Engineer and Illuminate Chromatin Folding in Live Human Cells

Chung, Y.-C.; Willey, S.; He, S.-L.; Wise, N.; Tu, L.-C.

2026-08-11 cell biology 10.64898/2026.08.09.743771 medRxiv
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Chromatin organization plays a critical role in regulating gene expression. Chromatin compaction represses gene expression by physically restricting the access of the transcriptional machinery to DNA, while spatial proximity between enhancers and promoters, often mediated by chromatin loops, is essential for gene activation. To investigate the regulatory mechanisms underlying loop formation and chromatin compaction, as well as their effects on gene expression, we developed CRISPR-FOIL (utilizing CRISPR to FOld and ILluminate chromosomal DNA), a novel programmable platform for engineering chromatin loops and inducing chromatin compaction in live cells. CRISPR-FOIL anchors pairs of genomic loci in proximity by engineered single-guide RNAs (sgRNAs), resulting in an artificial chromatin loop. The fused two CRISPR-Sirius gRNAs enable genomic loci to be visualized through fluorescent RNA coat proteins in various colors. In addition, multiple CRISPR-FOIL complexes can act cooperatively to drive chromatin compaction. These results establish CRISPR-FOIL as a powerful tool for engineering chromatin organization in live cells and highlight its potential as a therapeutic platform for gene regulation and disease control.

3
Molecular Basis For Pink1 Maturation

Xue, J.; Xu, H.; Zhang, Y.; Yu, X.; Du, Y.; Guo, J.; Duan, J.; Zhang, W.; Liu, X.; Gao, Y.; Chen, S.; Sui, S.-f.; Qin, X.; Liu, Z.; Mi, L.-Z.

2026-08-23 biophysics 10.64898/2026.08.19.745883 medRxiv
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Phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1), a key regulator of mitophagy, has been linked to the pathogenesis of Parkinson's disease (PD). PINK1 recruits Parkin, an E3 ubiquitin ligase, triggering mitophagy in response to mitochondrial damage. During mitophagy, the quantity, stability, and activity of PINK1 must be strictly regulated; however, the mechanisms governing these parameters under cellular stress are still unclear. Herein, we determined the structural basis for PINK1 maturation mediated by heat shock protein 90/cell division cycle 37/FK506-binding protein 51 (HSP90/CDC37/FKBP51) chaperone complex. We identified PINK1-associated proteins using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and determined the structures of the complexes using Cryo-Electron Microscopy (Cryo-EM). Results showed that FKBP51 potentially interacts with a conserved leucine-proline-phenylalanine (LPF) motif on the activation loop of PINK1 and negatively regulates PINK1 functions in mitophagy. A PINK1 mutation located at the FKBP51 recognition site is linked to mitophagy deficiency, which can be partially rescued by specific inhibition of FKBP51. These findings reveal a general mechanism for PINK1 recognition by the HSP90/CDC37/FKBP51 chaperone complex and suggest a potential approach for upregulating PINK1 activity, which is impaired in PD.

4
Compact type II-D Cas9 nucleases for efficient and specific genome editing

Wang, Q.; Saleh, A.; Rao, G. S.; Kazlak, A. M.; Aman, R.; Mahfouz, M. M.

2026-08-21 bioengineering 10.64898/2026.08.17.745286 medRxiv
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Compact CRISPR nucleases are attractive for therapeutic genome editing because their small coding sequences facilitate delivery by adeno-associated virus. Type II-D Cas9 (Cas9d) enzymes constitute the most compact Cas9 subtype, yet only a few orthologs have demonstrated mammalian genome-editing activity, leaving it unclear whether this activity is general or exceptional. Here, we mined the IMG/M metagenomic database and identified five previously uncharacterized MG102-like Cas9d orthologs ([~]950 amino acids) that share the hallmark genomic, sequence, and structural features of type II-D Cas9. Two of them, Cas9d-1 and Cas9d-4, recognized a 5-NRC-3 protospacer-adjacent motif and edited endogenous human loci with efficiencies up to 20.1%, exceeding Streptococcus pyogenes Cas9 at one site, while producing deletion-biased outcomes and no detectable off-target activity. Notably, both orthologs edited more efficiently than the sole previously validated member of this lineage, MG102-2, when assayed side by side under identical conditions. These findings establish compact MG102-like Cas9d orthologs as robust and specific genome editors and provide promising, single-AAV- compatible scaffolds for in vivo therapeutic genome editing.

5
Compact type II-C Cas9 nucleases with expanded PAM access and high fidelity for therapeutic genome editing

Wang, Q.; Gundra, S. R.; Aman, R.; Saleh, A.; Kazlak, A. M.; Masood, M.; Hassan, N.; Mahfouz, M. M.

2026-08-20 bioengineering 10.64898/2026.08.17.745178 medRxiv
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Compact type II-C Cas9 nucleases are attractive for therapeutic genome editing because their small size enables packaging into adeno-associated viral (AAV) vectors, and their extended protospacer-adjacent motifs (PAMs) reduce off-target cleavage while expanding targeting scope. Yet characterized type II-C orthologs have edited mammalian cells far less efficiently than the canonical SpCas9. Here, we used embedding-based metagenomic mining of >4.7 x 10 proteins, combined with AlphaFold3 structure prediction and locus-context analysis, to identify three previously uncharacterized compact type II-C Cas9 orthologs, NsuCas9 (1,092 aa), PsuCas9 (1,084 aa), and GfoCas9 (1,074 aa), and benchmarked them in vitro and in human HEK293T cells. All three are robust RNA-guided nucleases with distinct PAM specificities (N CC, N NYAA, and N RHAA, respectively), divergent thermal profiles, and asymmetric sgRNA cross-compatibility. In human cells, PsuCas9 with an N ATAA PAM reaches 78.4% indels and matches or exceeds SpCas9 at multiple loci, representing the first natural compact type II-C ortholog reported to do so, while GfoCas9 and NsuCas9 add complementary coverage. All three show a strong deletion-biased repair signature and no detectable editing across 33 predicted off-target sites. These compact, high-fidelity nucleases expand the CRISPR targeting space for AAV-deliverable therapeutic editing.

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A native single-transcript TnpB architecture enables efficient virus-induced genome editing and visual screening of heritable progeny harboring phenotypically silent edits

Wang, R.; Liu, H.; Jia, S.; Bai, S.; Cao, X.; Li, D.; Sun, Y.

2026-09-10 plant biology 10.64898/2026.09.09.750255 medRxiv
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TnpB are ultra-compact RNA-guided nucleases, yet most reported systems require separate expression of the nuclease and cognate reRNA, eroding their size advantage and restricting viral delivery in plants. Here we demonstrate that ISDra2 TnpB harnesses its native overlapping architecture in which the reRNA sequence resides within the 3' coding region of TnpB, processing its own mRNA to generate functional reRNA and enabling single-transcript genome editing in plants. Only a 7-bp conserved motif followed by a 16-20 bp spacer directly downstream of the coding sequence suffices for editing, requiring no exogenous ribozymes or independent guide promoters. This ultra-compact design enables simultaneous packaging of the editing system and an NbPDS silencing module into a single TRV vector, achieving robust editing in systemic Nicotiana benthamiana tissues and establishing a dual VIGE-VIGS strategy for direct visual selection of heritable, transgene-free edited progeny via distinct albino phenotypes, reducing laborious large-scale genotyping even for targets lacking inherent visible traits.

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ZDHHC14-Mediated Palmitoylation of TBK1 Promotes Pathological Cardiac Hypertrophy via Type I Interferon Signaling Activation

Zhao, W.; Yang, Y.; Ge, G.; Xu, R.

2026-07-26 molecular biology 10.64898/2026.07.24.740659 medRxiv
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Pathological cardiac hypertrophy represents a common maladaptive response to cardiovascular stress and constitutes a major harbinger of heart failure. Although S-palmitoylation--a reversible post-translational modification--critically governs protein localization, trafficking, and stability, its involvement in cardiac hypertrophy remains poorly characterized. In this study, we aimed to explore the role and regulatory mechanism of a palmitoyltransferase, zinc finger DHHC-type palmitoyltransferase 14 (ZDHHC14), in cardiac hypertrophy. We found that ZDHHC14 was significantly upregulated in cardiac hypertrophy tissues from both human patients and mouse models. Cardiomyocyte-specific ZDHHC14 knockdown ameliorated transverse aortic constriction (TAC)-induced cardiac hypertrophy and dysfunction in male mice, whereas cardiac-specific ZDHHC14 overexpression via AAV9 exacerbated these pathological phenotypes. Mechanistically, TANK-binding kinase 1 (TBK1) was identified as a novel substrate of ZDHHC14 through interactomic screening. ZDHHC14 catalyzed TBK1 palmitoylation at cysteine 267, which in turn facilitated TBK1 phosphorylation and subsequent activation of type I interferon (IFN-I) signaling, ultimately promoting cardiac hypertrophy. Importantly, our findings demonstrate that the TBK1-C267S mutation rectifies ZDHHC14 overexpression-induced exacerbation of cardiac hypertrophy. This study illustrated a ZDHHC14-TBK1-IFN-I axis in regulating cardiac hypertrophy, which may provide a potential therapeutic target to ameliorate pathological cardiac hypertrophy.

8
In vivo gene disruption and homology-directed repair in muscles and muscle stem cells using CRISPR/Cas9

Peacker, B. L.; Lin, K.-H.; Lam, A.; Rios, C. L.; Zhu, K.; Goldstein, J. M.; Messemer, K.; Ellis, R.; Florea, M.; Kletzien, H.; Horwitz, N.; Bratti, A. D.; Paul, U. S.; Maier, M.; KC, M.; Liu, T.; Kakhki, S. A.; Xiao, R.; Vandenberghe, L.; Wagers, A. J.

2026-08-17 cell biology 10.64898/2026.06.30.735705 medRxiv
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Programmable endonucleases such as CRISPR/Cas9 provide powerful tools to edit mammalian genomes by engaging cellular mechanisms of DNA double-strand break (DSB) repair. CRISPR-catalysed homology-directed repair (CRISPR-HDR), though generally less efficient than other modes of DNA repair, holds particular promise to enable precise sequence replacement by targeted insertion of a homologous DNA template1,2. While recent studies have reported appreciable levels of HDR in cardiomyocytes in vivo3, skeletal muscle myofibres have historically been considered refractory to HDR-mediated genome editing4. Furthermore, how repair outcomes differ across tissues after systemic delivery of CRISPR/Cas9 editors, whether precise HDR editing can be achieved in regenerative tissue stem cells, and how developmental timing influences accessibility to CRISPR-induced repair remain unclear. Here, we use an adeno-associated virus (AAV)-delivered in vivo GFP-to-BFP colour-switching reporter system (AAV-GFP-to-BFP) to examine in vivo CRISPR-HDR with cellular- and tissue-level resolution. We find that postnatal cardiac muscle, skeletal muscle, and muscle stem cells undergo templated HDR at different rates across discrete developmental stages in mice. While HDR-edited muscle stem cells and myofibres were readily detectable after in vivo editing in juvenile mice, editing in neonatal mice yielded more efficient HDR in cardiac tissue. Based on these results, we adapted the CRISPR-HDR approach to rescue the therapeutically relevant Dmd mutation in mdx mice, demonstrating recoding to the wild-type protein sequence in both skeletal and cardiac muscles. These results provide a framework for advancing donor-templated DNA repair in living postnatal animals, and reveal unexpected cellular, developmental, and disease-related constraints on precise, therapeutic in vivo gene correction.

9
SEME enables programmable transcript reconstruction through synthetic microexon incorporation

Go, M.; Oh, J.; Moon, S.; Chen, E. Z.; Kim, B.; Suh, D.; Kim, S.; Kwon, C.; Lee, S.

2026-09-18 bioengineering 10.64898/2026.09.13.749216 medRxiv
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Precise correction of pathogenic mutations remains challenging for therapeutic applications because genome editing within protein-coding exons can generate unintended insertion-deletion byproducts that disrupt coding integrity and protein function. To address this limitation, we developed the Spliceable Editable Microexon Element (SEME), an intron-targeting platform that enables programmable microexon incorporation through endogenous splicing. In induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs), SEME corrected aberrant splicing caused by the dilated cardiomyopathy-associated FLNC c.2003A>G variant by restoring the five nucleotides missing from exon 12, thereby recovering filamin C expression. Together, these findings establish programmable microexon incorporation as a proof-of-concept strategy for correcting diverse disease-causing transcript defects.

10
A CRISPR-Cas9 platform for primary human hepatocytes enables arrayed screening and in vivo validation of HBV host factors

Stenzel, A. F.; Athanasiadis, A.; Dangas, G.; Park, P.; Maslarinou, A.; Moschogianni, E.; Cataneo, A. H. D.; Freije, C. A.; Zhou, Y.; Levenson, K. C.; Quirk, C.; Zou, C.; Schneider, W. M.; Aguzzi, A.; Rice, C. M.; de Jong, Y. P.; Michailidis, E.

2026-08-18 genomics 10.64898/2026.08.10.743996 medRxiv
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More than two million deaths annually are attributed to liver-related conditions, making primary human hepatocytes (PHH) an invaluable in vitro model for studying liver pathophysiology and the molecular mechanisms underlying hepatic diseases. However, because PHH do not proliferate in culture, CRISPR gene editing has been highly inefficient. Here, we report lipofection- and lentivirus-mediated protocols for CRISPR-Cas9 delivery in mouse-passaged primary human hepatocytes (mpPHH), a system that enables PHH expansion in liver-humanized mice. We achieve robust gene editing efficiencies exceeding 90% in mpPHH while maintaining cell viability. We demonstrate the utility of these protocols by disrupting CYP3A4 to impair xenobiotic metabolism and by showing that edited mpPHH efficiently engraft and expand in mice, generating liver-humanized animals. We establish the feasibility of arrayed CRISPR screening in mpPHH using an 85-gene screen to identify host factors influencing hepatitis B virus (HBV) infection, and validate key findings in humanized mice by targeting the HBV entry receptor SLC10A1 (NTCP), which reduced viral infection in vivo. Our methodology enables scalable genetic manipulation of mpPHH, opening new avenues for HBV research and liver disease modeling.

11
Structural and functional basis of the non-canonical human Dicer-tRNA complex

Di Fazio, A.; Hirschi, S.; Battistini, F.; Santos, N.; Boot, J.; Ajit, K.; Abdullah, A.; Alagia, A.; Orozco, M.; Gullerova, M.

2026-08-13 molecular biology 10.64898/2026.08.12.744379 medRxiv
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Human Dicer (hDicer) is a key enzyme in the RNA interference (RNAi) pathway that generates [~]21-22 nt micro-RNA (miRNAs) and small interfering RNAs (siRNAs). We have previously shown that hDicer also generates tRNA-derived small RNAs (tsRNAs), which mediate nuclear gene silencing and regulate hundreds of disease-associated genes. As powerful and evolutionarily conserved cellular regulators, tsRNAs emerged as an important class of small RNAs. Therefore, it is essential to understand their biogenesis. However, the molecular and structural basis of tRNA cleavage by hDicer, as well as the role of chemical modifications such as 5-methylcytosine (m5C), in this process, remain unknown. Here, we present the first structural insights into hDicer in complex with tRNA, obtained by cryo-electron microscopy (cryo-EM), selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) and molecular dynamics (MD) simulations. Our results reveal that tRNAs adopt alternative conformations that are recognized and processed by hDicer. Furthermore, we show that tRNA cleavage by hDicer is facilitated by the m5C modification deposited by Nop2/SUN RNA methyltransferase 2 (NSUN2). Collectively, our findings redefine tRNAs as bona fide hDicer substrates and uncover a modification-dependent biogenetic pathway that reshapes the current understanding of the origins and regulation of human small RNAs. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=73 SRC="FIGDIR/small/744379v1_ufig1.gif" ALT="Figure 1000"> View larger version (24K): org.highwire.dtl.DTLVardef@ad78aborg.highwire.dtl.DTLVardef@cd3a7dorg.highwire.dtl.DTLVardef@1bb2594org.highwire.dtl.DTLVardef@1a0427e_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Immunometabolic Reprogramming by Thyroid-Stimulating Antibodies Drives Orbital Adipogenesis via Histone Lactylation in Thyroid Eye Disease

Zhang, Y.; Ling, N.; Wu, M.; Zeng, L.; Chen, B.; Liu, W.; Li, Z.; Zhang, Y.; Li, X.; Li, X.; Mao, Y.; Huang, Y.; Zhou, S.; Wan, S.; Wang, H.; Tu, Y.; Wu, J.; Ye, M.; Wu, W.

2026-07-30 immunology 10.64898/2026.07.27.741014 medRxiv
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Thyroid eye disease (TED) is conventionally viewed as an autoimmune inflammatory disorder. However, the metabolic determinants driving orbital tissue remodeling remain largely undefined. Here, we uncover a paradigm-shifting mechanism whereby thyroid-stimulating antibodies (TSAbs) instigate profound metabolic reprogramming in orbital fibroblasts (OFs), driving a switch toward glycolysis and markedly elevating lactate production via the CREB/LDHA axis. Critically, we demonstrate that this TSAbs-induced metabolic perturbation is not a mere byproduct but the principal driver of pathology. Mechanistically, lactate functions as a signaling metabolite that directly potentiates adipogenesis via histone lactylation-dependent transcriptional activation of the master adipogenic regulators PPAR{gamma} and C/EBP. Collectively, our findings underscore metabolic reprogramming as a central pathogenic mechanism in TED, whereby autoimmune cues drive disease progression through metabolic-epigenetic crosstalk. This work substantiates the paradigm of TED as an immune- metabolic disorder.

13
Predicted structure of the complete CPLANE complex reveals novel interactors and mechanisms of Jbts17 during ciliogenesis

Gardner, T. P.; Prolomova, A.; Lee, C.; Marcotte, E. M.; Wallingford, J. B.

2026-10-06 cell biology 10.64898/2026.10.05.756796 medRxiv
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Cilia are highly conserved organelles that use hundreds of unique proteins to drive extracellular motility and serve as signaling hubs for eukaryotic cells. The Ciliogenesis and Planar Polarity Effector (CPLANE) protein complex controls basal body docking during early ciliogenesis and recruits the intraflagellar transport (IFT) proteins to the base of growing cilia. Leveraging recent advantages in deep learning neural networks and high-performance computing, we predict the structure of JBTS17, the largest CPLANE subunit, and the tertiary structure of the complete CPLANE complex, revealing direct contacts between JBTS17 and three other CPLANE members. We then used this model for an in silico protein-protein interaction screen that identified several novel JBTS17 interactors. Experiments in Xenopus confirmed a functional link in vivo between Jbts17 and the Spinocerebellar ataxia-associated protein TTBK2. The data provide new insights into mechanisms of CPLANE function during ciliogenesis and demonstrate the power of modeling protein complexes for the discovery of physical and functional protein interactions in cell homeostasis and disease.

14
Signatures of the neutralizing dengue virus-reactive memory B cell repertoire identified by multiplexed envelope dimer probes

Lowman, K. E.; Aogo, R. A.; Smith, S.; Broderson, Y.; Firdous, S.; Bhushan, G.; Thiono, D. J.; Mpingabo, P.; Henry, A. R.; Johnston, T. S.; Roberts-Torres, J.; Estrada, L.; Schramm, C. A.; Cheung, F.; Polanco, J. J.; Apps, R.; Gangler, K.; Cohen, J. I.; Jacobson, S.; Davidson, E.; Doranz, B. J.; Cherry, J.; Douagi, I.; Blacklaws, B. A.; Heeney, J. L.; de Silva, A. M.; Douek, D. C.; Katzelnick, L. C.

2026-09-16 infectious diseases 10.64898/2026.09.15.26363039 medRxiv
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Sequential dengue virus (DENV) infection is thought to induce long-lived protection against dengue. However, little is known about the specificity, phenotype, and repertoire of the enduring B cell response due to limitations in high-throughput methods. We used stabilized DENV envelope (E) dimers as probes for in-depth memory B cell repertoire characterization using two complementary sequencing strategies. Using Rapid Assembly, Transfection, and Production of Immunoglobulins (RATP-Ig), we isolated 227 DENV2 E dimer-specific memory B cells from an immune donor, of which 87% bound at least two serotypes, 68% bound the fusion loop (FL-sensitive), and 42% were neutralizing. Among the most neutralizing, cross-binding antibodies, the FL-sensitive antibodies had weaker but broad neutralization, including to other flaviviruses, whereas FL-agnostic antibodies mapped to E domain II and III and were potently neutralizing, but only against one or two serotypes. Competitive binding of the DENV1-4 E dimers distinguished the more potently neutralizing FL-agnostic antibodies and broad and potent anti ()-envelope dimer epitope (EDE) antibodies from the FL-sensitive antibodies. Further, analysis of the heavy chain complementarity determining region 3 (CDRH3) showed FL-sensitive and -EDE antibodies were more negatively charged, but anti-EDE antibodies were distinguished by longer and more aromatic CDRH3s. We then demonstrated how oligonucleotide-tagged DENV1-4 dimers and proteogenomic single-cell B cell receptor sequencing (LIBRA-seq) could identify memory B cells predicted to have potent neutralization based on DENV-binding and CDRH3 physiochemical properties. This study provides insight into the secondary DENV-specific B cell repertoire and approaches for identifying protective antibodies as part of large-screening efforts.

15
Chromatin-Assisted Targeting Enables Precise DNA Methylation Editing in Plants

Jacobsen, S. E.; He, Y.; Wang, M.; Buckley, T. J.; Boone, B. A.; Li, E.; Shin, J. Y.; Alvarado, N.; Xu, B.; Nguyen, A.; Wang, S.; Zhou, Y.; Feng, S.

2026-08-26 plant biology 10.64898/2026.08.25.747117 medRxiv
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Precise installation of DNA methylation at selected loci offers a powerful strategy for regulating gene expression without altering DNA sequence, but existing plant epigenome editors are constrained by limited efficiency, locus dependence, and genome-wide off-target methylation. Here, we developed SunTag-MQ1v variants incorporating TRBIP1, which promotes removal of the antagonistic H3K4me3 mark, and CHLAMY, an oligomerizing alpha crystalline domain protein from Chlamydomonas reinhardtii. TRBIP1 enhanced methylation and silencing at the Arabidopsis FWA promoter but caused widespread off-target methylation and severe developmental defects. Adding CHLAMY produced SunTag-CHLAMY-TRBIP1-MQ1v (designated as SunTag-NOVA), which successfully overcame the lethality and widespread off-target effects associated with direct TRBIP1-MQ1v fusions. We demonstrate that CHLAMY drives higher-order oligomerization of the editing complex, which enhances target specificity and mitigates off-target accumulation. SunTag-NOVA robustly installed DNA methylation and repressed transcription at the endogenous FWA, FT and TMM genes with minimal genome-wide off-target consequences. These results show that combining local chromatin modification with controlled effector assembly can improve targeted DNA methylation, and establish SunTag-NOVA as a specific epigenome-editing platform for plants.

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Patient-Derived Liver Cancer Organoids Reflect Tumor Biology and Their Growth Phenotype Correlates with Clinical Outcomes

Kim, Y. S.; Go, Y.-H.; Kim, H. S.; Seo, J.; Kim, D. o.; Hwang, D.-Y.; Yang, W.; Lim, J. H.

2026-08-04 cancer biology 10.64898/2026.08.02.742347 medRxiv
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Liver cancer remains a major global health burden with high mortality and limited treatment response prediction tools. Patient-derived cancer organoids have emerged as promising preclinical models that recapitulate tumor heterogeneity; however, the biological significance of morphological diversity within established organoids remains poorly characterized in hepatocellular carcinoma (HCC). In this exploratory study, we investigated whether distinct organoid growth phenotypes reflect underlying tumor biology and correlate with clinical outcomes. We established liver cancer organoids from resected tumor tissues of 27 patients and analyzed their clinical, histological, and genomic characteristics. Organoids were classified morphologically into cystic and solid types. Whole exome sequencing (WES) was conducted on six matched tumor-organoid pairs to assess genomic fidelity. Associations between organoid establishment, growth characteristics, and clinical parameters were statistically evaluated. Progression-free survival (PFS) was analyzed using the Kaplan-Meier method and univariate Cox proportional hazards regression. Organoids were successfully established in 13 of 27 cases (48.1%). Solid-type organoids were significantly associated with shorter PFS compared to cystic types (HR = 13.91; p = 0.0039, log-rank test). Organoid establishment was more frequent in older patients (>70 years), those with HBV infection, and tumors with positive {beta}-catenin expression. WES analysis demonstrated high concordance in somatic mutation profiles and variant allele frequency distributions between tissues and corresponding organoids. In univariate Cox regression, organoid growth pattern (solid vs. cystic) showed a significant association with PFS within this exploratory cohort (p = 0.0207). Patient-derived liver cancer organoids preserved the genomic and histopathological features of the original tumors. Notably, solid morphology was associated with shorter PFS, suggesting that organoid growth phenotype may serve as a supplementary indicator of tumor biological behavior in HCC. Given the modest cohort size and the absence of multivariate analysis, these preliminary findings should be interpreted with caution and warrant further large-scale validation.

17
Epitope-Focused Immunogens Confer Broad Protection against Coronaviruses

Li, M.; Chen, Q.; Seo, J.; Liu, Y.; Peng, F.; Huang, K.; Dai, Z.; Chen, C.; Zhang, Z.; Zhao, J.; Wang, Z.; Yuan, F.; Ma, X.; Martinez, D. R.; Li, D.

2026-08-04 bioengineering 10.64898/2026.08.02.742375 medRxiv
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Variable regions in coronavirus spike dominate antibody responses elicited by infection or conventional vaccination and limit induction of broad neutralization. In contrast, conserved S2 elements, including the stem helix (SH) and fusion peptide proximal region (FPPR), are promising but subdominant targets of protective immunity. Here, we employed computational design to generate de novo epitope-focused immunogens that precisely present the SH and FPPR epitopes. Formulated as combinatorial immunogens, this vaccine elicited consistent serum responses with broad reactivity across known human coronaviruses and induced epitope-specific antibodies with broad neutralizing activity. As a heterologous boost, epitope-focused immunogens protected mice against challenge with phylogenetically distinct coronaviruses, including bat SARS-related RsSHC014-CoV and MERS-CoV, establishing a generalizable strategy for precision immune focusing and advancing universal coronavirus vaccine development.

18
A Novel and Evolutionarily Conserved Metabolic Axis for Efficient Hepatic Lipid Catabolism Governed by Mfn2-Hsl-Mediated Mitochondria-Lipid Droplet Coupling

Chi, Y.-J.; Liu, Z.-X.; Hu, N.-J.; Feng, G.-L.; Song, Y.

2026-09-29 cell biology 10.64898/2026.09.28.754920 medRxiv
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Inter-organelle contact between mitochondria and lipid droplets (LDs) is crucial for hepatic lipid homeostasis, but the tethering complex underlying this interaction remains unclear. To address this, we aimed to characterize the molecular machinery governing mitochondria-LD coupling and evaluate the evolutionary conservation of its metabolic functions. Using hepatocyte models from multiple species and in vivo experiments in yellow catfish with differential lipid and creatine diets, we explored the mechanism and evolutionary conservation of mitochondria-LD coupling. The key findings were: (1) A novel complex formed by mitofusin 2 on mitochondria and hormone-sensitive lipase on lipid droplets via specific residues orchestrates efficient hepatic lipid catabolism by mediating mitochondria-LD coupling; (2) Creatine enhances this coupling by transcriptionally upregulating mfn2 via hnf4, thereby promoting peridroplet mitochondria formation and alleviating hepatic lipid accumulation; (3) The Mfn2-phosphorylated HSL axis is evolutionarily conserved across fish and mammals, representing a potential therapeutic target for hepatic steatosis.

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Bivalent CK2 Inhibition as a Potent Strategy Against SARS-CoV-2 and Other Coronaviruses

Salomon Lopez Molina, D.; Ahnou, N.; Brillet, R.; Delcros, J.-G.; Softic, L.; Jimenez Araya, B.; Duval, M.; Veruete, M.; Bancet, A.; Grenier, D.; Mularoni, A.; Pawlotsky, J.-M.; Krimm, I.; Ahmed-Belkacem, A.

2026-10-05 microbiology 10.64898/2026.10.05.756735 medRxiv
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Protein kinase CK2 (CK2), a ubiquitously expressed serine/threonine kinase, has emerged as a key host factor exploited by several viruses, including Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we investigate the role of CK2 subunits in SARS-CoV-2 replication and evaluate the antiviral potential and broad-spectrum anti-coronavirus activity of two CK2 inhibitors: the previously described ATP-competitive inhibitor CX-4945 and a newly developed, highly selective bivalent inhibitor, AB668. The siRNA-mediated knockdown of CK2 subunits significantly reduced SARS-CoV-2 replication, highlighting its essential role in the viral lifecycle. Co-immunoprecipitation assays revealed that the SARS-CoV-2 nucleoprotein interacts with CK2. Furthermore, bio-layer interferometry assays demonstrated that the nucleoprotein specifically binds to the tetrameric CK2 holoenzyme (CK22{beta}2) but not to individual CK2 or CK2{beta} subunits. Pharmacological inhibition of CK2 with AB668 exhibited potent antiviral activity, significantly reducing viral replication by targeting a pre-replicative or RNA-replicative step of the viral life cycle. Importantly, AB668 displayed broad-spectrum antiviral activity, effectively inhibiting both HCoV-OC43 ({beta}-CoV) and HCoV-229E (-CoV). In summary, our findings establish CK2 as a critical host factor for SARS-CoV-2 replication and identify AB668 as a promising candidate for broad-spectrum antiviral therapy. With its high selectivity, minimized off-target effects, and efficacy against multiple coronaviruses, AB668 represents a valuable chemobiological and therapeutic tool.

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Floss-Mediated Gingival Mucosal Immunization with HBc-E18-3 VLPs Induces Long-Lasting Intestinal IgG and Provides a Candidate Strategy for Intervention of FcRn-Related Autoimmune Injury

Zhai, T.; Jiang, S.

2026-08-18 immunology 10.64898/2026.08.10.743934 medRxiv
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Echovirus 18 (E18) is a predominant pathogen causing aseptic meningitis in children, and post-E18 infection frequently triggers myasthenia gravis-like autoimmune neurological damage. This pathological process relies on neonatal Fc receptor (FcRn)-mediated IgG transcytosis across mucosal barriers, and FcRn also acts as an essential functional receptor required for E18 attachment and uncoating during host cell invasion. At present, no E18-specific prophylactic vaccine has been clinically approved, and anti-FcRn monoclonal antibodies are the available therapeutics to alleviate autoantibody-mediated tissue injury. We constructed an integrated automated phylogenetic pipeline named evolution_conservation, which enables rapid tracing of the evolutionary position and genetic relatedness of clinical isolates to identify closely related strains from previous outbreaks. Serving as an in silico alternative to animal experiments, this pipeline supports reference-guided vaccine design and longitudinal comparative assessment of vaccine safety and efficacy, facilitates identification of patient populations presenting rare post-viral sequelae, and accelerates clinical trial progression. In this study, we inserted the pre-screened linear epitope E18-3 into a truncated hepatitis B core (HBc) scaffold to generate chimeric virus-like particles (VLPs). A non-invasive floss-based gingival mucosal immunization mouse model was established, with subcutaneous Freunds adjuvant immunization set as the control group. ELISA results confirmed that gingival mucosal delivery of particulate HBc-E18-3 VLPs alone could induce sustained high levels of antigen-specific intestinal IgG in vivo. Drawing on research paradigms of therapeutic neoantigen vaccines for tumor recurrence prevention, the evolution_conservation bioinformatic pipeline and mucosal VLP platform described herein establish an innovative framework for developing antigen-competitive prophylactic and therapeutic vaccines targeting FcRn for myasthenia gravis and autoimmune encephalitis.