Histone Acetylation Research Articles

EP300‐interacting inhibitor of differentiation 3 is required for spermatogenesis in mice

AbstractBackgroundMammalian spermatogenesis is a highly complex process of cell proliferation, meiosis, and differentiation. A series of genes are expressed in an orderly and precise manner to ensure spermatogenesis, with chromatin undergoing intricate changes throughout. EP300‐interacting inhibitor of differentiation 3 (Eid3) is a testis‐enriched gene, but its role in male reproduction remains unclear.ObjectiveTo investigate the role of EID3 in male spermatogenesis and explore the potential underlying mechanism.Materials and MethodsWe generated Eid3 knockout mouse model using the CRISPR‐Cas9 system. We measured the expression of EID3 in mouse tissues and testicular cell populations by qRT‐PCR and western blot. Histological analysis, including hematoxylin and eosin (H&E) and periodic acid‐Schiff (PAS) staining, together with computer‐assisted sperm analysis (CASA), were performed to evaluate the effect of EID3 on spermatogenesis in mice. Light and ultrastructural microscopy were used to evaluate the morphology and structure of the Eid3−/− spermatozoa. We used western blot and immunofluorescence to further analyze the function of EID3 in spermiogenesis.ResultsEid3−/− mouse showed a significant decrease in sperm count, motility, and morphology. Loss of EID3 impaired the normal meiotic process and induced apoptosis of abnormally developing spermatocytes, ultimately resulting in the decrease of sperm cell number. Additionally, EID3 deficiency led to a decrease in histone acetylation levels in spermatids, impaired histone‐to‐protamine transition and chromatin condensation process, and ultimately resulted in abnormal sperm morphology.Discussion and ConclusionsThis study confirms for the first time that EID3 is crucial for meiosis and chromatin condensation during spermatogenesis, and EID3 deficiency leads to a significant decrease in sperm parameters. Given the high expression paradigm of Eid3 in human testis, EID3 likely plays a role in human reproduction. Future research could provide a new target for the clinical diagnosis and treatment of male infertility.

Lactate reprograms glioblastoma immunity through CBX3-regulated histone lactylation.

Glioblastoma (GBM), an aggressive brain malignancy with a cellular hierarchy dominated by GBM stem cells (GSCs), evades antitumor immunity through mechanisms that remain incompletely understood. Like most cancers, GBMs undergo metabolic reprogramming toward glycolysis to generate lactate. Here, we show that lactate production by patient-derived GSCs and microglia/macrophages induces tumor cell epigenetic reprogramming through histone lactylation, an activating modification that leads to immunosuppressive transcriptional programs and suppression of phagocytosis via transcriptional upregulation of CD47, a "don't eat me" signal, in GBM cells. Leveraging these findings, pharmacologic targeting of lactate production augments efficacy of anti-CD47 therapy. Mechanistically, lactylated histone interacts with the heterochromatin component chromobox protein homolog 3 (CBX3). Although CBX3 does not possess direct lactyltransferase activity, CBX3 binds histone acetyltransferase (HAT) EP300 to induce increased EP300 substrate specificity toward lactyl-CoA and a transcriptional shift toward an immunosuppressive cytokine profile. Targeting CBX3 inhibits tumor growth by both tumor cell-intrinsic mechanisms and increased tumor cell phagocytosis. Collectively, these results suggest that lactate mediates metabolism-induced epigenetic reprogramming in GBM that contributes to CD47-dependent immune evasion, which can be leveraged to augment efficacy of immuno-oncology therapies.

The role of histone post-translational modifications in cancer and cancer immunity: functions, mechanisms and therapeutic implications

Histones play crucial roles in both promoting and repressing gene expression, primarily regulated through post-translational modifications (PTMs) at specific amino acid residues. Histone PTMs, including methylation, acetylation, ubiquitination, phosphorylation, lactylation, butyrylation, and propionylation, act as important epigenetic markers. These modifications influence not only chromatin compaction but also gene expression. Their importance extends to the treatment and prevention of various human diseases, particularly cancer, due to their involvement in key cellular processes. Abnormal histone modifications and the enzymes responsible for these alterations often serve as critical drivers in tumor cell proliferation, invasion, apoptosis, and stemness. This review introduces key histone PTMs and the enzymes responsible for these modifications, examining their impact on tumorigenesis and cancer progression. Furthermore, it explores therapeutic strategies targeting histone PTMs and offers recommendations for identifying new potential therapeutic targets.

Role of the CTCF/p300 axis in osteochondrogenic-like differentiation of polyploid giant cancer cells with daughter cells.

Polyploid giant cancer cells (PGCCs) have properties of cancer stem cells (CSCs). PGCCs with daughter cells (PDCs) undergo epithelial-mesenchymal transition and show enhanced cellular plasticity. This study aimed to elucidate the mechanisms underlying the osteo/chondrogenic-like differentiation of PDCs, which may be exploited therapeutically by transdifferentiation into post-mitotic and functional cells. Cobalt chloride was used to induce PGCC formation in MDA-MB-231 and HEY cells, and PDCs were cultured in osteo/chondrogenic differentiation media. Alcian blue staining was used to confirm osteo/chondrogenic differentiation, and the cell cycle was detected using flow cytometry. The expression of osteo/chondrogenic differentiation-related proteins was compared, and a co-immunoprecipitation assay was used to demonstrate the interactions between proteins. Bioinformatic analysis was used to explore the regulatory mechanism of osteo/chondrogenic differentiation, and a dual-luciferase reporter assay was performed to validate the interaction between transcriptional factors and target genes. Animal xenograft models were used to confirm the osteo/chondrogenic differentiation of PDCs. When cultured in osteo/chondrogenic medium, the stemness of PDCs decreased, and the expression of osteo/chondrogenic-related markers increased. This osteo/chondrogenic-like process was regulated by the transforming growth factor-β pathway in a time-dependent manner. A concurrent increase in the expression of histone acetyltransferase p300 and the transcription factor CCCTC-binding factor (CTCF) was observed. Co-immunoprecipitation assays revealed that p300 acetylated the osteo/chondrogenic marker RUNT-related transcription factor 2 (RUNX2). Analysis of chromatin immunoprecipitation sequencing datasets revealed that both CTCF and histone H3 lysine 27 acetylation (H3K27ac) were enriched in the promoter region of E1A-associated protein p300 (P300). The four predicted binding sites for CTCF and P300 were validated using dual-luciferase reporter assays. We examined the interaction between CTCF and H3K27ac and found that these two proteins had a combined effect on the transactivation of P300. CTCF, in synergy with H3K27ac, amplified the expression of P300, facilitating acetyl group transfer to RUNX2. This acetylation stabilized RUNX2 and promoted osteo/chondrogenic differentiation, thereby reducing the incidence of PDC malignancies.

Increased COX6A2 promotes pancreatic β-cell apoptosis and is suppressed in diabetic GK rats after Roux-en-Y gastric bypass.

Roux-en-Y gastric bypass (RYGB) has been shown to inhibit β-cell apoptosis, but the underlying mechanisms are not yet fully understood. Cytochrome c oxidase subunit 6A2 (COX6A2) is expressed in β-cells. Here, we sought to investigate the role of COX6A2 in β-cell apoptosis, especially following RYGB. We found that RYGB significantly reduced β-cell apoptosis, accompanied by decreased COX6A2 expression in islets from diabetic Goto-Kakizaki (GK) rats. It is noteworthy that overexpression of COX6A2 promoted β-cell apoptosis, whereas COX6A2 deficiency suppressed it, suggesting the pro-apoptotic role of COX6A2 in β-cells. Mechanistically, increased COX6A2 interacted with and upregulated the expression of cyclophilin D (CypD), facilitating the release of cytochrome c from mitochondria to the cytoplasm, thereby promoting β-cell apoptosis. Furthermore, high-glucose-activated ChREBP epigenetically regulated COX6A2 expression by recruiting histone acetyltransferase p300 to augment histone H3 acetylation at the Cox6a2 promoter, a process inhibited by GLP-1 signaling. Given that RYGB enhances GLP-1 signaling, RYGB is likely to deactivate ChREBP by boosting GLP-1/PKA signaling, thereby reducing COX6A2 expression in islets from GK rats. These findings highlight the crucial role of the GLP-1/PKA/ChREBP axis-controlled COX6A2 in β-cell apoptosis, revealing a previously unrecognized mechanism underlying the reduction in β-cell apoptosis induced by RYGB.

Multifunctional acyltransferase HBO1: a key regulatory factor for cellular functions.

HBO1, also known as KAT7 or MYST2, is a crucial histone acetyltransferase with diverse cellular functions. It typically forms complexes with protein subunits or cofactors such as MEAF6, ING4, or ING5, and JADE1/2/3 or BRPF1/2/3, where the BRPF or JADE proteins serve as the scaffold targeting histone H3 or H4, respectively. The histone acetylation mediated by HBO1 plays significant roles in DNA replication and gene expression regulation. Additionally, HBO1 catalyzes the modification of proteins through acylation with propionyl, butyryl, crotonyl, benzoyl, and acetoacetyl groups. HBO1 undergoes ubiquitination and degradation by two types of ubiquitin complexes and can also act as an E3 ubiquitin ligase for the estrogen receptor α (ERα). Moreover, HBO1 participates in the expansion of medullary thymic epithelial cells (mTECs) and regulates the expression of peripheral tissue genes (PTGs) mediated by autoimmune regulator (AIRE), thus inducing immune tolerance. Furthermore, HBO1 influences the renewal of hematopoietic stem cells and the development of neural stem cells significantly. Importantly, the overexpression of HBO1 in various cancers suggests its carcinogenic role and potential as a therapeutic target. This review summarizes recent advancements in understanding HBO1's involvement in acylation modification, DNA replication, ubiquitination, immunity, and stem cell renewal.

The Impact of Alcohol-Induced Epigenetic Modifications in the Treatment of Alcohol use Disorders.

Alcohol use disorders are responsible for 5.9% of all death annually and 5.1% of the global disease burden. It has been suggested that alcohol abuse can modify gene expression through epigenetic processes, namely DNA and histone methylation, histone acetylation, and microRNA expression. The alcohol influence on epigenetic mechanisms leads to molecular adaptation of a wide number of brain circuits, including the hypothalamus-hypophysis-adrenal axis, the prefrontal cortex, the mesolimbic-dopamine pathways and the endogenous opioid pathways. Epigenetic regulation represents an important level of alcohol-induced molecular adaptation in the brain. It has been demonstrated that acute and chronic alcohol exposure can induce opposite modifications in epigenetic mechanisms: acute alcohol exposure increases histone acetylation, decreases histone methylation and inhibits DNA methyltransferase activity, while chronic alcohol exposure induces hypermethylation of DNA. Some studies investigated the chromatin status during the withdrawal period and the craving period and showed that craving was associated with low methylation status, while the withdrawal period was associated with elevated activity of histone deacetylase and decreased histone acetylation. Given the effects exerted by ethanol consumption on epigenetic mechanisms, chromatin structure modifiers, such as histone deacetylase inhibitors and DNA methyltransferase inhibitors, might represent a new potential strategy to treat alcohol use disorder. Further investigations on molecular modifications induced by ethanol might be helpful to develop new therapies for alcoholism and drug addiction targeting epigenetic processes.

Repurposing Plant-Based Histone Acetyltransferase Inhibitors: A Review of Novel Therapeutic Strategies Against Drug-Resistant Fungal Biofilms.

The rapid emergence of drug-resistant fungal strains necessitates the development of novel therapeutic approaches for battling biofilm-related infections. Biofilms, efflux pumps, and suppression of virulence traits in pathogenic yeasts are governed by epigenetic enzymes, namely, histone acetyltransferases (HATs) and histone deacetylases (HDACs). The review article is focused on the use of histone acetyltransferase inhibitors (HATi), a mechanism-based epidrug that inactivates the regular function of HATs. With an emphasis on specific plant-based HATi and their Structure-Activity Relationship (SAR), the review enumerates the extensive list of anticancer HATi that can be screened for antifungal activities. By repurposing these anticancer HATi, this approach may help generate broad-spectrum antifungal medications that highlight common biological pathways between fungus and cancer, possibly revolutionizing both treatment domains.

Histone Modification Pathways Suppressing Cryptic Transcription

Cryptic transcription refers to the unintended expression of non-canonical sites within the genome, producing aberrant RNA and proteins that may disrupt cellular functions. In this opinion piece, I will explore the role of histone modifications in modulating cryptic transcription and its implications for gene expression and cellular integrity, particularly with a focus on H3K36 and H3K4 methylation marks. H3K36 tri-methylation plays a crucial role in maintaining chromatin integrity by facilitating the recruitment of the Rpd3S histone deacetylase (HDAC) complex, which helps restore closed chromatin states following transcription and prevents cryptic initiation within gene bodies. In parallel, crosstalk between H3K4 di-methylation and histone ubiquitylation and sumoylation is critical for recruiting the Set3 HDAC complex, which maintains low histone acetylation levels in gene bodies and further suppresses cryptic transcription. Therefore, by elucidating these regulatory mechanisms, this opinion highlights the intricate interplay of histone modifications in preserving transcriptional fidelity and suggests potential pathways for future research to develop novel therapies for age-related disorders and other diseases associated with dysregulated gene expression.

Metabolically inducing defects in DNA repair sensitizes BRCA-wild-type cancer cells to replication stress.

Metabolic reprogramming from oxidative respiration to glycolysis is generally considered to be advantageous for tumor initiation and progression. However, we found that breast cancer cells forced to perform glycolysis acquired a vulnerability to PARP inhibitors. Small-molecule inhibition of mitochondrial respiration-using glyceollin I, metformin, or phenformin-induced overproduction of the oncometabolite lactate, which acidified the extracellular milieu and repressed the expression of homologous recombination (HR)-associated DNA repair genes. These serial events created so-called "BRCAness," in which cells exhibit an HR deficiency phenotype despite lacking germline mutations in HR genes such as BRCA1 and BRCA2, and, thus, sensitized the cancer cells to clinically available poly(ADP-ribose) polymerase inhibitors. The increase in lactate repressed HR-associated gene expression by decreasing histone acetylation. These effects were selective to breast cancer cells; normal epithelial cells retained HR proficiency and cell viability. These mechanistic insights into the BRCAness-prone properties of breast cancer cells support the therapeutic utility and cancer cell-specific potential of mitochondria-targeting drugs.

DNAR-15. GROUP 3 MEDULLOBLASTOMAS EXPLOIT A TRANSIENT MECHANISM OF TELOMERE REPAIR MEDIATED BY ZSCAN4 WHICH IS TARGETABLE FOR THERAPEUTIC BENEFIT WITH BRAIN-PENETRANT DRUGS

Abstract All cancers need some mechanism of telomere repair. However, it is unknown how Group 3 (G3) medulloblastomas (MB) repair their telomeres, even though MB is the most common malignant brain tumor in kids and G3 is its most aggressive subtype. With rare exceptions, G3 MBs lack telomerase gain-of-function alterations or evidence of constitutive alternative-lengthening-of-telomeres pathway activation. We profiled tumors from N=38 MB patients from UCSF via single-nucleus RNA sequencing; 13 cases were also subjected to single-cell assay for transposase-accessible chromatin by sequencing, and 4 were subjected to single-cell cleavage under targets and tagmentation for H3K27ac. These data identified a network of gene enhancers that were specifically active in rhombic-lip progenitor-like MB cells, the putative G3 MB cell of origin. This program was driven by zinc finger and SCAN domain containing 4 (ZSCAN4), a gene reported to drive transient telomere repair during zygotic genome activation in early embryos. CRISPR inhibition of ZSCAN4 led to significant telomere shortening, telomeric DNA damage, telomere fusions, decreased proliferation, and increased survival of orthotopic xenografts. Conversely, ZSCAN4 over-expression induced significant telomere elongation, increased proliferation, and decreased survival in vivo. Analysis of endogenous-reporter cells indicated that ZSCAN4 is transiently expressed in response to telomere shortening and increases global histone acetylation by inducing chromatin-remodeling factors. Rebastinib targeted ZSCAN4, histone acetylation, and telomere repair, was brain penetrant, and significantly enhanced orthotopic-xenograft survival with no toxicity. Acetyltransferase inhibitor CPI-1612 was brain penetrant and extended xenograft survival with no toxicity. Our data support the hypothesis that G3 MBs exploit a transient mechanism of telomere repair mediated by ZSCAN4. Targeting ZSCAN4 or downstream histone acetylation is therapeutically viable. Pan-cancer whole-genome sequencing data showed that MBs have lower telomeric content than most other cancers. Thus, MBs may be particularly vulnerable to therapeutic strategies that inhibit telomere repair.

CSIG-07. JAK1/STAT1/3 COOPERATES WITH THE CIC-FUSIONS TO DRIVE CIC-REARRANGED SARCOMAS

Abstract CIC-rearranged sarcoma (CRS) is an rare disease driven by a specific fusion protein involving the CIC gene. Occurrence in the brain is 3% in all CRS patients. The native CIC protein is a transcriptional repressor of the (RTK)/Ras/ERK signaling pathway, which is one of the most tumorigenic pathways in cancer. The most common rearrangement is with the double homeobox 4 (DUX4) transcription factor (CIC-DUX4), and others, such as CIC-NUTM1 fusions, have been identified in a subset of pediatric primitive neuroectodermal tumors. However, the molecular mechanisms by which CIC-fusions drive CRS remain unknown. Preliminary data shows that CIC-DUX4/NUTM1 fusions activate JAK and its downstream effector STAT1/3. We hypothesize that the JAK/STAT1/3 signal transduction pathway cooperates with CIC-fusions to induce the expression of oncogenic transcription factors ETV1/4/5 and drive these sarcomas. We show high levels of JAK1/STAT1/3 activation in patient-derived CRS cell lines (NCC-SCC-89/C) as compared to other sarcoma cell lines without the fusion. JAK1 inhibition using Solicitinib and Ruxolitinib reduced phosphorylation of STAT1/3 as well as protein and mRNA expression of ETV1/4/5, promoter activity of ETV5, cell proliferation and tumorgenicity. Interestingly DUX4 is involved in histone acetylation and STAT1 has been shown to activate p300/CBP complex which lead us to evaluating the role of STAT1 in the gene activation CRS. We elucidate mechanistically that the fusion proteins increase binding of STAT1/3 at the promoters of ETV 1/4/5. Importantly, JAK1 inhibition effectively reduces histone acetylation induced by CIC-fusions at the promoters of ETV1/4/5. To evaluate the pre-clinical effect of targeting the JAK1/STAT1/3 pathway, A CRS cell line (NCC-SCC-89/C) were grafted into NSG mice. Ruxolitinib treatment significantly reduced tumor volume, STAT activation, and ETV1/4/5. In conclusion, we show that the JAK1/STAT1/3 pathway plays a critical role in cooperating with CIC-fusions to drive CRS, providing insight into potential therapeutic avenues for these aggressive tumors.

Pharmacological inhibition of astrocytic transglutaminase 2 facilitates the expression of a neurosupportive astrocyte reactive phenotype in association with increased histone acetylation.

Astrocytes play critical roles in supporting structural and metabolic homeostasis in the central nervous system (CNS). CNS injury leads to the development of a range of reactive phenotypes in astrocytes whose molecular determinants are poorly understood. Finding ways to modulate astrocytic injury responses and leverage a pro-recovery phenotype holds promise in treating CNS injury. Recently, it has been demonstrated that ablation of astrocytic transglutaminase 2 (TG2) modulates the phenotype of reactive astrocytes in a way that improves neuronal injury outcomes both in vitro and in vivo . In an in vivo mouse model, pharmacological inhibition of TG2 with the irreversible inhibitor VA4 phenocopies the neurosupportive effects of TG2 deletion in astrocytes. In this study, we provide insights into the mechanisms by which TG2 deletion or inhibition result in a more neurosupportive astrocytic phenotype. Using a neuron-astrocyte co-culture model, we show that VA4 treatment improves the ability of astrocytes to support neurite outgrowth on an injury-relevant matrix. To better understand how pharmacologically altering TG2 affects its ability to regulate reactive astrocyte phenotypes, we assessed how VA4 inhibition impacts TG2's interaction with Zbtb7a, a transcription factor we have previously identified as a functionally relevant TG2 nuclear interactor. The results of these studies demonstrate that VA4 significantly decreases the interaction of TG2 and Zbtb7a. TG2's interactions with Zbtb7a, as well as a wide range of other transcription factors and chromatin regulatory proteins, suggest that TG2 may act as an epigenetic regulator to modulate gene expression. To begin to understand if TG2-mediated epigenetic modification may impact astrocytic phenotypes in our models, we interrogated the effect of TG2 deletion and VA4 treatment on histone acetylation and found significantly greater acetylation in both experimental groups. Consistent with these findings, previous RNA-sequencing and our present proteomic analysis also supported a predominant transcriptionally suppressive role of TG2 in astrocytes. Our proteomic data additionally unveiled pronounced changes in lipid and antioxidant metabolism in astrocytes with TG2 deletion or inhibition, which likely contribute to the enhanced neurosupportive function of these astrocytes.

DDDR-21. MPT0G521 AS A DUAL INHIBITOR OF LSD1 AND HDAC: A POTENTIAL THERAPEUTIC AGENT AGAINST PARENTAL AND TEMOZOLOMIDE-RESISTANT GLIOBLASTOMA MULTIFORME

Abstract INTRODUCTION Glioblastoma multiforme (GBM) is an aggressive brain tumor with limited treatment options and poor prognosis. Resistance to temozolomide (TMZ), the standard chemotherapy for GBM, further complicates treatment. This study investigates the effects of MPT0G521, a dual inhibitor of LSD1 and HDAC, on both parental and TMZ-resistant GBM cells to determine its potential as a therapeutic agent. MATERIALS AND METHODS TMZ and MPT0G521 were introduced in our study. Human GBM cell lines A172 and patient-derived primary GBM cells Pt#3, along with their TMZ-resistant counterparts, were cultured under specified conditions. Assays conducted include cell proliferation (MTT), colony formation, cell cycle analysis via flow cytometry, and western blot analysis for protein expression. Statistical significance was evaluated using ANOVA. RESULTS MPT0G521 exhibited significant anti-proliferative activity and toxicity against both parental and TMZ-resistant GBM cells in a dose- and time-dependent manner. Treatment with MPT0G521 led to reduced cell viability and colony formation. Cell cycle analysis revealed G2M phase arrest and increased subG1 phase, indicating cell cycle disruption and apoptosis. Western blot analysis showed upregulation of histone H3 methylation and acetylation, confirming the dual inhibitory action of MPT0G521 on LSD1 and HDAC. Additionally, MPT0G521 modulated markers of cell cycle and apoptosis, including increased levels of cleaved caspase-3 and PARP. CONCLUSION MPT0G521 demonstrates potential as an effective therapeutic agent against GBM by inhibiting cell proliferation, inducing cell cycle arrest, and promoting apoptosis in both parental and TMZ-resistant cells. These findings support further investigation of MPT0G521 as a promising treatment for GBM, particularly in cases resistant to standard chemotherapy.

EXTH-34. ACETYLATION SUPPRESSION MEETS ONCOLYTIC VIRUSES FOR THE TREATMENT OF PEDIATRIC DIFFUSE MIDLINE GLIOMA

Abstract Diffuse midline glioma (DMG) remains a devastating pediatric brain tumor without effective treatment. In a recent clinical trial, we demonstrated the feasibility and efficacy of Delta-24-RGD oncolytic virus combined with radiation therapy in patients with newly diagnosed diffuse intrinsic pontine gliomas (NCT03178032). Because the adenoviral protein E1A binds to P300 and redirects acetylation upon virus infection, we hypothesized that combining oncolytic adenoviruses with P300 inhibitors will cause a remarkable shifting in acetylation and the post-translational landscape of DMG, ultimately enhancing the anti-glioma effect of oncolytic viruses. Western blot analyses showed a longitudinal reduction in H3K27ac (89%) and H3K18ac (99%) in a panel of human (TP54 and SF8628) and murine (24B_1 and 26C_7) DMG cells after Delta-24-RGD infection. In addition, using histone fractionation by high-performance liquid chromatography, we detected an increase in total H3 upon adenovirus infection. Mass spectrometry of histones in the human DIPG cell line, TP54 using middle-down approach illustrated post-translational changes across histones, including hypoacetylation of the H3.2K14 mark. To further modify histone acetylation in DMG during Delta-24-RGD infection, we combined virotherapy with C646, a selective and competitive histone acetyltransferase inhibitor of the E1A-binding p300/CBP complex of proteins. In vitro, the combination of Delta-24-RGD with C646 synergistically increased cell death in a panel of human and murine DIPG cell lines (zip-scores ranging from 6.3-11.3 with zip-scores above 10 being indicative of synergy). Ongoing experiments using a panel of adenoviruses expressing E1A with defective P300 binding or expressing a dominant-negative form of P300 or wild-type P300 are designed to test the extent to which E1A binding of P300 drives hypoacetylation in DMG upon virus infection. In addition, we are performing in vivo experiments to establish the anti-cancer effect of the combination of Delta-24-RGD and P300 inhibitors in clinically relevant animal models of DMG, with a feasible translation to the clinic.

Wheat Topoisomerase VI Positively Regulates the Biosynthesis of Cuticular Wax and Cutin.

Lipophilic cuticles mainly composed of wax mixtures and cutin matrices seal the plant epidermis and control plant development and environmental adaptation. Although cuticle-associated traits have been selected in the breeding of agronomically important cereal bread wheat, the biosynthesis of wheat cuticular wax and cutin remains poorly understood. Herein, wheat topoisomerase VI was characterized as an essential activator of cuticular wax and cutin biosynthesis. Knock-down of wheat TaTOP6A, TaTOP6B, TaRHL1, or TaBIN4 gene encoding component of topoisomerase VI resulted in decreased loads of leaf cuticular wax and cutin, as well as increased leaf cuticle permeability. Moreover, TaCYP86A2 was identified as a key component of the wheat cutin biosynthetic machinery. Reduction of wheat TaCYP86A2 expression led to decreased cutin accumulation and enhanced cuticle permeability. In addition, TaTOP6A, TaTOP6B, TaRHL1, or TaBIN4 was shown to enrich at the promoter regions of the wax biosynthesis gene TaKCS1 and the cutin biosynthesis gene TaCYP86A2. Importantly, chromatin at TaKCS1 and TaCYP86A2 promoters is marked by high nucleosome occupancy and low histone acetylation in TaTOP6A-, TaTOP6B-, TaRHL1-, or TaBIN4-silenced wheat leaves. These results collectively support that wheat topoisomerase VI positively regulates the biosynthesis of cuticular wax and cutin probably via maintaining a permissive chromatin state at TaKCS1 and TaCYP86A2 genes.

DNA Methylation and Histone Acetylation Contribute to the Maintenance of LTP in the Withdrawal Behavior Interneurons in Terrestrial Snails

Accumulated data indicate that epigenetic regulations, including histone modifications and DNA methylation, are important means for adjusting the expression of genes in response to various stimuli. In contrast to the success in studying the role of DNA methylation in laboratory rodents, the role of DNA methylation in the terrestrial snail Helix lucorum has been studied only in behavioral experiments. This prompted us to further investigate the role of DNA methylation and the interaction between DNA methylation and histone acetylation in the mechanisms of neuroplasticity in terrestrial snails using in vitro experiments. Dysregulation of DNA methylation by the DNMT inhibitor RG108 significantly suppressed the long-term potentiation (LTP) of synaptic inputs in identified neurons. We then tested whether the RG108-induced weakening of potentiation can be reversed under co-application of histone deacetylase inhibitors sodium butyrate or trichostatin A. It was found that increased histone acetylation significantly compensated for RG108-induced LTP deficiency. These data bring important insights into the functional role of DNA methylation as an important regulatory mechanism and a necessary condition for the development and maintenance of long-term synaptic changes in withdrawal interneurons of terrestrial snails. Moreover, these results support the idea of the interaction of DNA methylation and histone acetylation in the epigenetic regulation of synaptic plasticity.

Validation of selective catalytic BmCBP inhibitors that regulate the Bm30K-24 protein expression in silkworm, Bombyx mori.

The cAMP response element binding protein (CREB)-binding protein (CBP) is a histone acetyltransferase that plays an indispensable role in regulating the acetylation of histone and non-histone proteins. Recently, it has been discovered that chemical inhibitors A485 and C646 can bind to Bombyx mori's CBP (BmCBP) and inhibit its acetyltransferase activity. Notably, the binding ability of A485 with BmCBP showed a very low Kd value of 48 nM by surface plasmon resonance (SPR) test. Further identification showed that both A485 and C646 can decrease the acetylation level of known substrate H3K27 and only 1 μM of A485 can almost completely inhibit the acetylation of H3K27, suggesting that A485 is an effective inhibitor of BmCBP's acetyltransferase activity. Moreover, it was confirmed that A485 could downregulate the expression of acetylated Bm30K-24 protein at a post-translational level through acetylation modification by BmCBP. Additionally, it was found that A485 can downregulate the stability of Bm30K-24 and improve its ubiquitination level, suggesting that the acetylation modification by BmCBP could compete with ubiquitination modification at the same lysine site on Bm30K-24, thereby affecting its protein stability. Here, we predict that A485 may be a potent CBP acetyltransferase inhibitor which could be utilized to inhibit acetyltransferase activity in insects, including silkworms.

ANK Deficiency-Mediated Cytosolic Citrate Accumulation Promotes Aortic Aneurysm.

Disturbed metabolism and transport of citrate play significant roles in various pathologies. However, vascular citrate regulation and its potential role in aortic aneurysm (AA) development remain poorly understood. Untargeted metabolomics by mass spectrometry was applied to identify upregulated metabolites of the tricarboxylic acid cycle in AA tissues of mice. To investigate the role of citrate and its transporter ANK (progressive ankylosis protein) in AA development, vascular smooth muscle cell (VSMC)-specific Ank-knockout mice were used in both Ang II (angiotensin II)- and CaPO4-induced AA models. Citrate was abnormally increased in both human and murine aneurysmal tissues, which was associated with downregulation of ANK, a citrate membrane transporter, in VSMCs. The knockout of Ank in VSMCs promoted AA formation in both Ang II- and CaPO4-induced AA models, while its overexpression inhibited the development of aneurysms. Mechanistically, ANK deficiency in VSMCs caused abnormal cytosolic accumulation of citrate, which was cleaved into acetyl coenzyme A and thus intensified histone acetylation at H3K23, H3K27, and H4K5. Cleavage under target and tagmentation analysis further identified that ANK deficiency-induced histone acetylation activated the transcription of inflammatory genes in VSMCs and thus promoted a citrate-related proinflammatory VSMC phenotype during aneurysm diseases. Accordingly, suppressing citrate cleavage to acetyl coenzyme A downregulated inflammatory gene expression in VSMCs and restricted ANK deficiency-aggravated AA formation. Our studies define the pathogenic role of ANK deficiency-induced cytosolic citrate accumulation in AA pathogenesis and an undescribed citrate-related proinflammatory VSMC phenotype. Targeting ANK-mediated citrate transport may emerge as a novel diagnostic and therapeutic strategy in AA.

Epigenetic Effects of Natural Products in Inflammatory Diseases: Recent Findings.

Inflammation is an essential step for the etiology of multiple diseases. Clinically, due to the limitations of current drugs for the treatment of inflammatory diseases, such as serious side effects and expensive costs, it is urgent to explore novel mechanisms and medicines. Natural products have received extensive attention recently because of their multi-component and multi-target characteristics. Epigenetic modifications are crucial pathophysiological targets for developing innovative therapies for pharmacological interventions. Investigations examining how natural products improving inflammation through epigenetic modifications are emerging. This review state that natural products relieve inflammation via regulating the gene transcription levels through chromosome structure regulated by histone acetylation levels and the addition or deletion of methyl groups on DNA duplex. They could also exert anti-inflammatory effects by modulating the proteins in typical inflammatory signaling pathways by ubiquitin-related degradation and the effect of glycolysis derived free glycosyls. Studies on epigenetic modifications have the potential to facilitate the development of natural products as therapeutic agents. Future research directed at better understanding of how natural products modulate inflammatory processes through less studied epigenetic modifications including neddylation, SUMOylation, palmitoylation and lactylation, may provide new implications. Meanwhile, higher quality preclinical studies and more powerful clinical evidence are still needed to firmly establish the clinical efficacy of the natural products. Trial Registration: ClinicalTrials.gov Identifier: NCT01764204; ClinicalTrials.gov Identifier: NCT05845931; ClinicalTrials.gov Identifier: NCT04657926; ClinicalTrials.gov Identifier: NCT02330276.