Depressive symptoms and associated factors among older patients with arthritis: evidence from a community-based study in eastern China.

Introduction: Depressive symptoms are often experienced by patients with arthritis and are correlated with poor health outcomes. However, the association between depressive symptoms and multidimensional factors (sociodemographic characteristics, health conditions, health behaviors, and social support) among older patients with arthritis in China remains poorly understood. This study aimed to explore the prevalence of depressive symptoms in older patients with arthritis in eastern China and identify the associated factors. Methods: We analyzed data of 1,081 older patients with arthritis using secondary data from 2014 to 2020 from a community-based ongoing study initiated in 2014 in eastern China. The prevalence of depressive symptoms was calculated, and univariate and multilevel logistic regression analyses were used to identify the associated factors. Results: The mean age of older patients with arthritis was 69.16 ± 7.13 years; 42.92% were men and 57.08% were women. The prevalence of depressive symptoms in older patients with arthritis was 14.99% (95% confidence interval: 12.91-17.26%), about 1.8 times higher than that in older adults without arthritis (8.49%, p < 0.001). Multilevel logistic regression identified perception of poor economic status (odds ratio [OR] = 5.52, p < 0.001), multimorbidity (OR = 1.96, p = 0.001), limitations in activities of daily living (OR = 2.36, p = 0.004), and living alone (OR = 3.13, p = 0.026) as factors positively associated with depressive symptoms. Patients diagnosed with arthritis at an older age had lower odds of experiencing depressive symptoms (OR = 0.67, p = 0.046). Conclusion: Screening for depressive symptoms is essential among older patients with arthritis, especially those who perceive themselves as having a poor economic status, are diagnosed at an earlier age, have multimorbidity, have limitations in activities of daily living, and live alone. The associations of age at arthritis diagnosis and dietary behaviors with depressive symptoms require further research.

Structural basis of pri-let-7 recognition by human pseudouridine synthase TruB1.

Let-7 was one of the first microRNAs (miRNAs) to be discovered and its expression promotes differentiation during development and function as tumor suppressors in various cancers. The maturation process of let-7 miRNA is tightly regulated by multiple RNA-binding proteins. For example, LIN28 binds to the terminal loops of the precursors of let-7 family and block their processing into mature miRNAs. Trim25 promotes the uridylation-mediated degradation of pre-let-7 modified by LIN28/TUT4. Recently, human pseudouridine synthase TruB1 has been reported to facilitate let-7 maturation by directly binding to pri-let-7 and recruiting Drosha-DGCR8 microprocessor. Through biochemical assay and structural investigation, we show that human TruB1 binds specifically the terminal loop of pri-let-7a1 at nucleotides 31-41, which folds as a small stem-loop architecture. Although TruB1 recognizes the terminal loop of pri-let-7a1 in a way similar to how E. coli TruB interacts with tRNA, a conserved KRKK motif in human and other higher eukaryotes adds an extra binding interface and strengthens the recognition of TruB1 for pri-let-7a1 through electrostatic interactions. These findings reveal the structural basis of TruB1-pri-let-7 interaction which may assists the elucidation of precise role of TruB1 in biogenesis of let-7.

Synergistically enhancing electrocatalysis and non-enzymatic sensing for glucose by iridium single-atom/nickel oxide/N-doped graphene.

The development of novel catalyst with high catalytic activity is important for electrochemical non-enzymatic glucose sensing. Here, iridium single-atom/nickel oxide nanoparticle/N-doped graphene nanosheet (Ir1/NiO/NG) with the loading of 1.13 wt% Ir was successfully synthesized for constructing electrochemical non-enzymatic glucose sensor for the first time. The morphology and structure of Ir1/NiO/NG were characterized by XRD, SEM, TEM, HRTEM, and XPS, and the presence of Ir SAs was confirmed by AC-HAADF-STEM. The Ir1/NiO/NG shows 65 mV lower oxidation potential and 3.3 times higher response current than Ni(OH)2/NG. In addition, Ir1/NiO/NG exhibits high sensitivity (70.09 µA mM-1 cm-2), excellent selectivity, low detection limit (2.00 µM), and great stability (91.53% current remaining after 21 days) for electrochemical non-enzymatic glucose sensing. The outstanding catalytic and sensing performance of Ir1/NiO/NG is mainly attributed to synergistic effect of Ir SAs, NiO nanoparticles, and highly conductive NG, which modulate the electronic and geometric structure of Ir1/NiO/NG. This work shows the promising potential of SACs in electrochemical sensing.

Identification of an SCF ubiquitin ligase complex that contributes to resistance against Valsa canker in apple.

E3 ubiquitin ligases play a critical role in plant disease resistance. Among them, the SCF (Skp1-Cullin-F-box protein) ubiquitin ligase complex is the largest family and regulates the ubiquitination of a wide range of proteins. Apple Valsa canker (AVC) is a fungal disease of apple trees caused by the fungus Valsa mali, which can lead to significant economic losses. However, the function of the SCF complex in apple resistance to this disease is still largely unknown. In this study, we identified an SCF ubiquitin ligase complex that can enhance resistance to Valsa canker in apple. Disease evaluation experiments demonstrated that MdSkp1 increased apple resistance to AVC. Furthermore, MdSkp1 interacted with an F-box protein, MdSKIP14, and a cullin-1 protein, MdCUL1, to form an SCF ubiquitin ligase complex. Additionally, we revealed both MdSKIP14 and MdCUL1 as positive regulators of AVC resistance. In conclusion, our results identified an SCF complex capable of contributing to apple resistance against AVC, providing a theoretical basis for apple disease resistance and the sustainable development of the industry.

Major depressive disorder and the risk of irritable bowel syndrome: A Mendelian randomization study.

BACKGROUND: The association between major depressive disorder (MDD) and irritable bowel syndrome (IBS) has been found in observational research; however, the causative relationship between MDD and IBS remains uncertain. Using the two-sample Mendelian randomization (MR) approach, we attempted to examine the causal effect of MDD on IBS. METHODS: Independent genetic variants for MDD identified by Howard et al. based on a genome-wide meta-analysis were selected for this study. Gene-Outcome associations for IBS were gathered from UK Biobank and FinnGen databases. The MR analysis included inverse variance weighted (IVW), MR-Egger regression, weighted median, weighted mode, and MR-PRESSO sensitivity analyses. RESULTS: FinnGen database subjected to inverse variance weighted (IVW) analysis revealed that MDD may be a risk factor for the development of IBS (OR = 1.356, 95% CI: 1.125-1.632, p = 0.0013). The same finding was reached in UK Biobank for IVW (OR = 1.011, 95% CI: 1.006-1.015, p = 3.18 × 10-7 ), MR-Egger progression (OR = 1.030, 95% CI: 1.008-1.051, p = 0.007), and weighted median (OR = 1.011, 95% CI: 1.005-1.016, p = 0.0001). CONCLUSION: Our findings supported a causal relationship between MDD and IBS, which may have implications for the clinical management of IBS in individuals with MDD.

Structural insights into the recognition of the A/T-rich motif in target gene promoters by the LMX1a homeobox domain.

LIM homeodomain transcription factor 1-alpha (LMX1a) is a neuronal lineage-specific transcription activator that plays an essential role during the development of midbrain dopaminergic (mDA) neurons. LMX1a induces the expression of multiple key genes, which ultimately determine the morphology, physiology, and functional identity of mDA neurons. This function of LMX1a is dependent on its homeobox domain. Here, we determined the structures of the LMX1a homeobox domain in complex with the promoter sequences of the Wnt family member 1 (WNT1) or paired like homeodomain 3 (Pitx3) gene, respectively. The complex structures revealed that the LMX1a homeobox domain employed its α3 helix and an N-terminal loop to achieve specific target recognition. The N-terminal loop (loop1) interacted with the minor groove of the double-stranded DNA (dsDNA), whereas the third α-helix (α3) was tightly packed into the major groove of the dsDNA. Structure-based mutations in the α3 helix of the homeobox domain significantly reduced the binding affinity of LMX1a to dsDNA. Moreover, we identified a nonsyndromic hearing loss (NSHL)-related mutation, R199, which yielded a more flexible loop and disturbed the recognition in the minor groove of dsDNA, consistent with the molecular dynamics (MD) simulations. Furthermore, overexpression of Lmx1a promoted the differentiation of SH-SY5Y cells and upregulated the transcription of WNT1 and PITX3 genes. Hence, our work provides a detailed elucidation of the specific recognition between the LMX1a homeobox domain and its specific dsDNA targets, which represents valuable information for future investigations of the functional pathways that are controlled by LMX1a during mDA neuron development.

Structural insights into curdlan degradation via a glycoside hydrolase containing a disruptive carbohydrate-binding module.

BACKGROUND: Degradation via enzymatic processes for the production of valuable ß-1,3-glucooligosaccharides (GOS) from curdlan has attracted considerable interest. CBM6E functions as a curdlan-specific ß-1,3-endoglucanase, composed of a glycoside hydrolase family 128 (GH128) module and a carbohydrate-binding module (CBM) derived from family CBM6. RESULTS: Crystallographic analyses were conducted to comprehend the substrate specificity mechanism of CBM6E. This unveiled structures of both apo CBM6E and its GOS-complexed form. The GH128 and CBM6 modules constitute a cohesive unit, binding nine glucoside moieties within the catalytic groove in a singular helical conformation. By extending the substrate-binding groove, we engineered CBM6E variants with heightened hydrolytic activities, generating diverse GOS profiles from curdlan. Molecular docking, followed by mutation validation, unveiled the cooperative recognition of triple-helical ß-1,3-glucan by the GH128 and CBM6 modules, along with the identification of a novel sugar-binding residue situated within the CBM6 module. Interestingly, supplementing the CBM6 module into curdlan gel disrupted the gel's network structure, enhancing the hydrolysis of curdlan by specific ß-1,3-glucanases. CONCLUSIONS: This study offers new insights into the recognition mechanism of glycoside hydrolases toward triple-helical ß-1,3-glucans, presenting an effective method to enhance endoglucanase activity and manipulate its product profile. Furthermore, it discovered a CBM module capable of disrupting the quaternary structures of curdlan, thereby boosting the hydrolytic activity of curdlan gel when co-incubated with ß-1,3-glucanases. These findings hold relevance for developing future enzyme and CBM cocktails useful in GOS production from curdlan degradation.

Biomechanical Comparison of Anterior Cervical Corpectomy Decompression and Fusion, Anterior Cervical Discectomy and Fusion, and Anterior Controllable Antedisplacement and Fusion in the Surgical Treatment of Multilevel Cervical Spondylotic Myelopathy: A Finite Element Analysis.

PURPOSE: Multilevel cervical spondylotic myelopathy poses significant challenges in selecting optimal surgical approaches, warranting a comprehensive understanding of their biomechanical impacts. Given the lack of consensus regarding the most effective technique, this study aims to fill this critical knowledge gap by rigorously assessing and comparing the biomechanical properties of three distinct surgical interventions, including anterior controllable antedisplacement and fusion (ACAF), anterior cervical corpectomy decompression and fusion (ACCF), and anterior cervical discectomy and fusion (ACDF). The study offers pivotal insights to enhance treatment precision and patient outcomes. METHODS: The construction of the cervical spine model involved a detailed process using CT data, specialized software (Mimics, Geomagic Studio, and Hypermesh) and material properties obtained from prior studies. Surgical instruments were modeled (titanium mesh, anterior cervical plate, interbody cage, and self-tapping screws) to simulate three surgical approaches: ACAF, ACCF, and ACDF, each with specific procedures replicating clinical protocols. A 75-N follower load with 2 Nm was applied to simulate biomechanical effects. RESULTS: The range of motion decreased more after surgery for ACAF and ACDF than for ACCF, especially in flexion and lateral bending. ACCF have higher stress peaks in the fixation system than those of ACAF and ACDF, especially in flexion. The maximum von Mises stresses of the bone-screw interfaces at C3 of ACCF were higher than those of ACAF and ACDF. The maximum von Mises stresses of the bone-screw interfaces at C6 of ACDF were much higher than those of ACAF and ACCF. The maximum von Mises stresses of the grafts of ACCF and ACAF were much higher than those of ACDF. The maximum von Mises stresses of the endplate of ACCF were much higher than those of ACAF and ACDF. CONCLUSION: The ACAF and ACDF models demonstrated superior cervical reconstruction stability over the ACCF model. ACAF exhibited lower risks of internal fixation failure and cage subsidence compared to ACCF, making it a promising approach. However, while ACAF revealed improved stability over ACCF, higher rates of subsidence and internal fixation failure persisted compared to ACDF, suggesting the need for further exploration of ACAF's long-term efficacy and potential improvements in clinical outcomes.

Catalytic Nanodots-Driven Pyroptosis Suppression in Nucleus Pulposus for Antioxidant Intervention of Intervertebral Disc Degeneration.

Low back pain resulting from intervertebral disc degeneration (IVDD) is a prevalent global concern; however, its underlying mechanism remains elusive. Single-cell sequencing analyses revealed the critical involvement of pyroptosis in IVDD. Considering the involvement of reactive oxygen species (ROS) as the primary instigator of pyroptosis and the lack of an efficient intervention approach, this study developed carbonized Mn-containing nanodots (MCDs) as ROS-scavenging catalytic biomaterials to suppress pyroptosis of nucleus pulposus (NP) cells to efficiently alleviate IVDD. Catalytic MCDs have superior efficacy in scavenging intracellular ROS and rescuing homeostasis in the NP microenvironment compared with N-acetylcysteine, a classical antioxidant. The data validates that pyroptosis plays a vital role in mediating the protective effects of catalytic MCDs against oxidative stress. Systematic in vivo assessments substantiate the effectiveness of MCDs in rescuing a puncture-induced IVDD rat model, further demonstrating their ability to suppress pyroptosis. This study highlights the potential of antioxidant catalytic nanomedicine as a pyroptosis inhibitor and mechanistically unveils an efficient strategy for the treatment of IVDD.

Structural insights into the specific recognition of mitochondrial ribosome-binding factor hsRBFA and 12 S rRNA by methyltransferase METTL15.

Mitochondrial rRNA modifications are essential for mitoribosome assembly and its proper function. The m4C methyltransferase METTL15 maintains mitochondrial homeostasis by catalyzing m4C839 located in 12 S rRNA helix 44 (h44). This modification is essential to fine-tuning the ribosomal decoding center and increasing decoding fidelity according to studies of a conserved site in Escherichia coli. Here, we reported a series of crystal structures of human METTL15-hsRBFA-h44-SAM analog, METTL15-hsRBFA-SAM, METTL15-SAM and apo METTL15. The structures presented specific interactions of METTL15 with different substrates and revealed that hsRBFA recruits METTL15 to mitochondrial small subunit for further modification instead of 12 S rRNA. Finally, we found that METTL15 deficiency caused increased reactive oxygen species, decreased membrane potential and altered cellular metabolic state. Knocking down METTL15 caused an elevated lactate secretion and increased levels of histone H4K12-lactylation and H3K9-lactylation. METTL15 might be a suitable model to study the regulation between mitochondrial metabolism and histone lactylation.

Valsa mali PR1-like protein modulates an apple valine-glutamine protein to suppress JA signaling-mediated immunity.

Apple Valsa canker (AVC) is a devastating disease of apple (Malus × domestica), caused by Valsa mali (Vm). The Cysteine-rich secretory protein, Antigen 5, and Pathogenesis-related protein 1 (CAP) superfamily protein PATHOGENESIS-RELATED PROTEIN 1-LIKE PROTEIN c (VmPR1c) plays an important role in the pathogenicity of Vm. However, the mechanisms through which it exerts its virulence function in Vm-apple interactions remain unclear. In this study, we identified an apple valine-glutamine (VQ)-motif-containing protein, MdVQ29, as a VmPR1c target protein. MdVQ29-overexpressing transgenic apple plants showed substantially enhanced AVC resistance as compared with the wild type. MdVQ29 interacted with the transcription factor MdWRKY23, which was further shown to bind to the promoter of the jasmonic acid (JA) signaling-related gene CORONATINE INSENSITIVE 1 (MdCOI1) and activate its expression to activate the JA signaling pathway. Disease evaluation in lesion areas on infected leaves showed that MdVQ29 positively modulated apple resistance in a MdWRKY23-dependent manner. Furthermore, MdVQ29 promoted the transcriptional activity of MdWRKY23 toward MdCOI1. In addition, VmPR1c suppressed the MdVQ29-enhanced transcriptional activation activity of MdWRKY23 by promoting the degradation of MdVQ29 and inhibiting MdVQ29 expression and the MdVQ29-MdWRKY23 interaction, thereby interfering with the JA signaling pathway and facilitating Vm infection. Overall, our results demonstrate that VmPR1c targets MdVQ29 to manipulate the JA signaling pathway to regulate immunity. Thus, this study provides an important theoretical basis and guidance for mining and utilizing disease-resistance genetic resources for genetically improving apples.

Artificial intelligence-aided diagnostic imaging: A state-of-the-art technique in precancerous screening.

BACKGROUND AND AIM: Chromoendoscopy with the use of indigo carmine (IC) dye is a crucial endoscopic technique to identify gastrointestinal neoplasms. However, its performance is limited by the endoscopist's skill, and no standards are available for lesion identification. Thus, we developed an artificial intelligence (AI) model to replace chromoendoscopy. METHODS: This pilot study assessed the feasibility of our novel AI model in the conversion of white-light images (WLI) into virtual IC-dyed images based on a generative adversarial network. The predictions of our AI model were evaluated against the assessments of five endoscopic experts who were blinded to the purpose of this study with a staining quality rating from 1 (unacceptable) to 4 (excellent). RESULTS: The AI model successfully transformed the WLI of polyps with different morphologies and different types of lesions in the gastrointestinal tract into virtual IC-dyed images. The quality ratings of the real IC-dyed and AI images did not significantly differ concerning surface structure (AI vs IC: 3.08 vs 3.00), lesion border (3.04 vs 2.98), and overall contrast (3.14 vs 3.02) from 10 sets of images (10 AI images and 10 real IC-dyed images). Although the score depended significantly on the evaluator, the staining methods (AI or real IC) and evaluators had no significant interaction (P > 0.05) with each other. CONCLUSION: Our results demonstrated the feasibility of employing AI model's virtual IC staining, increasing the possibility of being employed in daily practice. This novel technology may facilitate gastrointestinal lesion identification in the future.

MdVQ12 confers resistance to Valsa mali by regulating MdHDA19 expression in apple.

Valine-glutamine (VQ) motif-containing proteins play a crucial role in plant biotic stress responses. Apple Valsa canker, caused by the ascomycete Valsa mali, stands as one of the most severe diseases affecting apple trees. Nonetheless, the underlying resistance mechanism of VQ proteins against this disease has remained largely unexplored. This study reports MdVQ12, a VQ motif-containing protein, as a positive regulator of apple Valsa canker resistance. Genetic transformation experiments demonstrated that MdVQ12 overexpression increased resistance to V. mali, while gene silencing lines exhibited significantly reduced resistance. MdVQ12 interacted with the transcription factor MdWRKY23, which bound to the promoter of the histone deacetylase gene MdHDA19, activating its expression. MdHDA19 enhanced apple resistance to V. mali by participating in the jasmonic acid (JA) and ethylene (ET) signalling pathways. Additionally, MdVQ12 promoted the transcriptional activity of MdWRKY23 towards MdHDA19. Our findings reveal that MdVQ12 enhances apple resistance to V. mali by regulating MdHDA19 expression and thereby regulating the JA and ET signalling pathways, offering potential candidate gene resources for breeding apple Valsa canker-resistant germplasm.

A Clinical Classification of Cervical Ossification of the Posterior Longitudinal Ligament to Guide Surgical Strategy.

STUDY DESIGN: A clinical classification of cervical ossification of the posterior longitudinal ligament (COPLL) was developed based on imaging findings. OBJECTIVE: This study aimed to establish a clinical classification for COPLL and provide corresponding surgery strategies for each subtype. SUMMARY OF BACKGROUND DATA: A practical and reliable classification is needed to guide the treatment of COPLL. MATERIALS AND METHODS: This study retrospectively reviewed plain radiographs, computed tomography scans, and magnetic resonance images of patients diagnosed with COPLL between 2018 and 2022 at Shanghai Changzheng Hospital. The types of COPLL were classified according to the location, morphology, and canal-occupying ratio (OR) of the ossification mass. Interobserver and intraobserver reliability were evaluated using Cohen's kappa. RESULTS: A total of 1000 cases were included, which were classified into five types: focal type (F type), short-sequential type (S type), long-sequential type (L type), high type (H type), and mixed type (M type). In addition, each type could be classified into subtype 1 or subtype 2 according to the canal-OR. Then each type could be further classified into other subtypes according to location and morphology. The interobserver reliabilities in the first and second rounds were 0.853 and 0.887, respectively. The intraobserver reliability was 0.888. CONCLUSION: The authors classified COPLL into a system comprised of five types and several subtypes according to canal-OR, location, and morphology. Surgical strategies for each subtype are also suggested. This provides a theoretical guide for the description and surgical management of COPLL.

Liver-Derived Ketogenesis via Overexpressing HMGCS2 Promotes the Recovery of Spinal Cord Injury.

The liver is the major ketogenic organ of the body, and ketones are reported to possess favorable neuroprotective effects. This study aims to elucidate whether ketone bodies generated from the liver play a critical role in bridging the liver and spinal cord. Mice model with a contusive spinal cord injury (SCI) surgery is established, and SCI induces significant histological changes in mice liver. mRNA-seq of liver tissue shows the temporal changes of ketone bodies-related genes, ß-hydroxybutyrate dehydrogenase (BDH1) and solute carrier family 16 (monocarboxylic acid transporters), member 6 (SLC16A6). Then, an activated ketogenesis model is created with adult C57BL/6 mice receiving the tail intravenous injection of GPAAV8-TBG-Mouse-Hmgcs2-CMV- mCherry -WPRE (HMGCS2liver ) and mice receiving equal AAV8-Null being the control group (Vectorliver ). Then, the mice undergo either a contusive SCI or sham surgery. The results show that overexpression of HMG-CoA synthase (Hmgcs2) in mice liver dramatically alleviates SCI-mediated pathological changes and promotes ketogenesis in the liver. Amazingly, liver-derived ketogenesis evidently alleviates neuron apoptosis and inflammatory microglia activation and improves the recovery of motor function of SCI mice. In conclusion, a liver-spinal cord axis can be bridged via ketone bodies, and enhancing the production of the ketone body within the liver has neuroprotective effects on traumatic SCI.

Lupenone improves motor dysfunction in spinal cord injury mice through inhibiting the inflammasome activation and pyroptosis in microglia via the nuclear factor kappa B pathway.

JOURNAL/nrgr/04.03/01300535-202408000-00034/figure1/v/2023-12-16T180322Z/r/image-tiff Spinal cord injury-induced motor dysfunction is associated with neuroinflammation. Studies have shown that the triterpenoid lupenone, a natural product found in various plants, has a remarkable anti-inflammatory effect in the context of chronic inflammation. However, the effects of lupenone on acute inflammation induced by spinal cord injury remain unknown. In this study, we established an impact-induced mouse model of spinal cord injury, and then treated the injured mice with lupenone (8 mg/kg, twice a day) by intraperitoneal injection. We also treated BV2 cells with lipopolysaccharide and adenosine 5'-triphosphate to simulate the inflammatory response after spinal cord injury. Our results showed that lupenone reduced IκBα activation and p65 nuclear translocation, inhibited NLRP3 inflammasome function by modulating nuclear factor kappa B, and enhanced the conversion of proinflammatory M1 microglial cells into anti-inflammatory M2 microglial cells. Furthermore, lupenone decreased NLRP3 inflammasome activation, NLRP3-induced microglial cell polarization, and microglia pyroptosis by inhibiting the nuclear factor kappa B pathway. These findings suggest that lupenone protects against spinal cord injury by inhibiting inflammasomes.

Valproic acid ameliorates cauda equina injury by suppressing HDAC2-mediated ferroptosis.

INTRODUCTION: Persistent neuroinflammatory response after cauda equina injury (CEI) lowers nociceptor firing thresholds, accompanied by pathological pain and decreasing extremity dysfunction. Histone deacetylation has been considered a key regulator of immunity, inflammation, and neurological dysfunction. Our previous study suggested that valproic acid (VPA), a histone deacetylase inhibitor, exhibited neuroprotective effects in rat models of CEI, although the underlying mechanism remains elusive. METHODS: The cauda equina compression surgery was performed to establish the CEI model. The Basso, Beattie, Bresnahan score, and the von Frey filament test were carried out to measure the animal behavior. Immunofluorescence staining of myelin basic protein and GPX4 was carried out. In addition, transmission electron microscope analysis was used to assess the effect of VPA on the morphological changes of mitochondria. RNA-sequencing was conducted to clarify the underlying mechanism of VPA on CEI protection. RESULTS: In this current study, we revealed that the expression level of HDAC1 and HDAC2 was elevated after cauda equina compression model but was reversed by VPA treatment. Meanwhile, HDAC2 knockdown resulted in the improvement of motor functions and pathologic pain, similar to treatment with VPA. Histology analysis also showed that knockdown of histone deacetylase (HDAC)-2, but not HDAC1, remarkably alleviated cauda equina injury and demyelinating lesions. The potential mechanism may be related to lowering oxidative stress and inflammatory response in the injured region. Notably, the transcriptome sequencing indicated that the therapeutic effect of VPA may depend on HDAC2-mediated ferroptosis. Ferroptosis-related genes were analyzed in vivo and DRG cells further validated the reliability of RNA-sequencing results, suggesting HDAC2-H4K12ac axis participated in epigenetic modulation of ferroptosis-related genes. CONCLUSION: HDAC2 is critically involved in the ferroptosis and neuroinflammation in cauda equina injury, and VPA ameliorated cauda equina injury by suppressing HDAC2-mediated ferroptosis.

ZNF524 directly interacts with telomeric DNA and supports telomere integrity.

Telomeres are nucleoprotein structures at the ends of linear chromosomes. In humans, they consist of TTAGGG repeats, which are bound by dedicated proteins such as the shelterin complex. This complex blocks unwanted DNA damage repair at telomeres, e.g. by suppressing nonhomologous end joining (NHEJ) through its subunit TRF2. Here, we describe ZNF524, a zinc finger protein that directly binds telomeric repeats with nanomolar affinity, and reveal base-specific sequence recognition by cocrystallization with telomeric DNA. ZNF524 localizes to telomeres and specifically maintains the presence of the TRF2/RAP1 subcomplex at telomeres without affecting other shelterin members. Loss of ZNF524 concomitantly results in an increase in DNA damage signaling and recombination events. Overall, ZNF524 is a direct telomere-binding protein involved in the maintenance of telomere integrity.

Insights into the missing apiosylation step in flavonoid apiosides biosynthesis of Leguminosae plants.

Apiose is a natural pentose containing an unusual branched-chain structure. Apiosides are bioactive natural products widely present in the plant kingdom. However, little is known on the key apiosylation reaction in the biosynthetic pathways of apiosides. In this work, we discover an apiosyltransferase GuApiGT from Glycyrrhiza uralensis. GuApiGT could efficiently catalyze 2″-O-apiosylation of flavonoid glycosides, and exhibits strict selectivity towards UDP-apiose. We further solve the crystal structure of GuApiGT, determine a key sugar-binding motif (RLGSDH) through structural analysis and theoretical calculations, and obtain mutants with altered sugar selectivity through protein engineering. Moreover, we discover 121 candidate apiosyltransferase genes from Leguminosae plants, and identify the functions of 4 enzymes. Finally, we introduce GuApiGT and its upstream genes into Nicotiana benthamiana, and complete de novo biosynthesis of a series of flavonoid apiosides. This work reports an efficient phenolic apiosyltransferase, and reveals mechanisms for its sugar donor selectivity.