IDH1/MDH1 deacetylation promotes NETosis by regulating OPA1 and autophagy.

BACKGROUND: As a heterogeneous and life-threatening disease, the pathogenesis of acute liver failure (ALF) is complex. Our previous study has shown that IDH1/MDH1 deacetylation promotes ALF by regulating NETosis (a novel mode of cell death). In this article, we explore the manners of IDH1/MDH1 deacetylation regulates NETosis. METHODS: In vitro experiments, the formation of NETs was detected by immunofluorescence staining and Western blotting. LC3 fluorescence staining was used to detect autophagosome formation. To observe mitochondrial morphology, cells were stained by Mito-Tracker Red. Western blotting was used to detect the levels of autophagy protein and mitochondrial dynamin. In vivo experiments, the ALF model in mouse was established with LPS/D-gal, and the formation of NETs was detected by immunofluorescence staining and Western blotting. The autophagy levels were detected by Western blotting in liver samples. RESULTS: In dHL-60 cells, Western blotting results showed that the expression of OPA1 was higher in the IDH1/MDH1 deacetylated group compared with the IDH1/MDH1 WT group. And histone deacetylase inhibitor 6 (HDAC6i, ACY1215) decreased the expression level of OPA1 in IDH1/MDH1 deacetylated group. IDH1/MDH1 deacetylation increased the expression levels of both LC3B-II and Beclin 1, while decreasing the expression level of P62. It was reversed by ACY1215. Combined with our previous experiments, IDH1/MDH1 deacetylation upregulated autophagy concomitant with the increased expression of the markers of NETs formation. In a mouse model of ALF, ACY1215 further decreased the expression levels of LC3B-II and Beclin 1, while increasing the expression level of P62 in IDH1/MDH1 deacetylated mice. CONCLUSIONS: IDH1/MDH1 deacetylation promoted NETosis by regulating autophagy and OPA1 in vitro. The regulation of neutrophil autophagy on NETosis during IDH1/MDH1 deacetylation might be masked in mice. ACY1215 might attenuate NETosis by regulating neutrophil autophagy, which alleviated ALF aggravated by IDH1/MDH1 deacetylation.

YkuR functions as a protein deacetylase in Streptococcus mutans.

Protein acetylation is a common and reversible posttranslational modification tightly governed by protein acetyltransferases and deacetylases crucial for various biological processes in both eukaryotes and prokaryotes. Although recent studies have characterized many acetyltransferases in diverse bacterial species, only a few protein deacetylases have been identified in prokaryotes, perhaps in part due to their limited sequence homology. In this study, we identified YkuR, encoded by smu_318, as a unique protein deacetylase in Streptococcus mutans. Through protein acetylome analysis, we demonstrated that the deletion of ykuR significantly upregulated protein acetylation levels, affecting key enzymes in translation processes and metabolic pathways, including starch and sucrose metabolism, glycolysis/gluconeogenesis, and biofilm formation. In particular, YkuR modulated extracellular polysaccharide synthesis and biofilm formation through the direct deacetylation of glucosyltransferases (Gtfs) in the presence of NAD+. Intriguingly, YkuR can be acetylated in a nonenzymatic manner, which then negatively regulated its deacetylase activity, suggesting the presence of a self-regulatory mechanism. Moreover, in vivo studies further demonstrated that the deletion of ykuR attenuated the cariogenicity of S. mutans in the rat caries model, substantiating its involvement in the pathogenesis of dental caries. Therefore, our study revealed a unique regulatory mechanism mediated by YkuR through protein deacetylation that regulates the physiology and pathogenicity of S. mutans.

Histone deacetylases: Regulation of vascular homeostasis via endothelial cells and vascular smooth muscle cells and the role in vascular pathogenesis.

Histone deacetylases (HDACs) are proteases that play a key role in chromosome structural modification and gene expression regulation, and the involvement of HDACs in cancer, the nervous system, and the metabolic and immune system has been well reviewed. Our understanding of the function of HDACs in the vascular system has recently progressed, and a significant variety of HDAC inhibitors have been shown to be effective in the treatment of vascular diseases. However, few reviews have focused on the role of HDACs in the vascular system. In this study, the role of HDACs in the regulation of the vascular system mainly involving endothelial cells and vascular smooth muscle cells was discussed based on recent updates, and the role of HDACs in different vascular pathogenesis was summarized as well. Furthermore, the therapeutic effects and prospects of HDAC inhibitors were also addressed in this review.

SIRT1-FOXOs signaling pathway: A potential target for attenuating cardiomyopathy.

Cardiomyopathy constitutes a global health burden. It refers to myocardial injury that causes alterations in cardiac structure and function, ultimately leading to heart failure. Currently, there is no definitive treatment for cardiomyopathy. This is because existing treatments primarily focus on drug interventions to attenuate symptoms rather than addressing the underlying causes of the disease. Notably, the cardiomyocyte loss is one of the key risk factors for cardiomyopathy. This loss can occur through various mechanisms such as metabolic disturbances, cardiac stress (e.g., oxidative stress), apoptosis as well as cell death resulting from disorders in autophagic flux, etc. Sirtuins (SIRTs) are categorized as class III histone deacetylases, with their enzyme activity primarily reliant on the substrate nicotinamide adenine dinucleotide (NAD (+)). Among them, Sirtuin 1 (SIRT1) is the most intensively studied in the cardiovascular system. Forkhead O transcription factors (FOXOs) are the downstream effectors of SIRT1. Several reports have shown that SIRT1 can form a signaling pathway with FOXOs in myocardial tissue, and this pathway plays a key regulatory role in cell loss. Thus, this review describes the basic mechanism of SIRT1-FOXOs in inhibiting cardiomyocyte loss and its favorable role in cardiomyopathy. Additionally, we summarized the SIRT1-FOXOs related regulation factor and prospects the SIRT1-FOXOs potential clinical application, which provide reference for the development of cardiomyopathy treatment.

Deacetylation by SIRT6 increases the stability of GILZ to suppress NSCLC cell migration and invasion.

Glucocorticoid-induced leucine zipper (GILZ) plays a role in cancer cell proliferation in several tumor types. However, in our present study, GILZ was demonstrated to be a metastasis regulator but not a proliferation regulator in non-small cell lung cancer (NSCLC). The overexpression of GILZ had no significant effect on the proliferation of NSCLC cells but inhibited their metastasis by targeting the epithelial-mesenchymal transition pathway. The deacetylase SIRT6, a key regulator of protein stability, can enhance the stability of the GILZ protein by mediating its deacetylation, which prevents ubiquitination and degradation. This process ultimately enhances the inhibitory effect of GILZ on the migration and invasion of NSCLC cells. Thus, GILZ may be a promising new therapeutic target for tumor metastasis.

SIRT1-mediated deacetylation of FOXO3 enhances mitophagy and drives hormone resistance in endometrial cancer.

BACKGROUND: The complex interplay between Sirtuin 1 (SIRT1) and FOXO3 in endometrial cancer (EC) remains understudied. This research aims to unravel the interactions of deacetylase SIRT1 and transcription factor FOXO3 in EC, focusing on their impact on mitophagy and hormone resistance. METHODS: High-throughput sequencing, cell experiments, and bioinformatics tools were employed to investigate the roles and interactions of SIRT1 and FOXO3 in EC. Co-immunoprecipitation (Co-IP) assay was used to assess the interaction between SIRT1 and FOXO3 in RL95-2 cells. Functional assays were used to assess cell viability, proliferation, migration, invasion, apoptosis, and the expression of related genes and proteins. A mouse model of EC was established to evaluate tumor growth and hormone resistance under different interventions. Immunohistochemistry and TUNEL assays were used to assess protein expression and apoptosis in tumor tissues. RESULTS: High-throughput transcriptome sequencing revealed a close association between SIRT1, FOXO3, and EC development. Co-IP showed a protein-protein interaction between SIRT1 and FOXO3. Overexpression of SIRT1 enhanced FOXO3 deacetylation and activity, promoting BNIP3 transcription and PINK1/Parkin-mediated mitophagy, which in turn promoted cell proliferation, migration, invasion, and inhibited apoptosis in vitro, as well as increased tumor growth and hormone resistance in vivo. These findings highlighted SIRT1 as an upstream regulator and potential therapeutic target in EC. CONCLUSION: This study reveals a novel molecular mechanism underlying the functional relevance of SIRT1 in regulating mitophagy and hormone resistance through the deacetylation of FOXO3 in EC, thereby providing valuable insights for new therapeutic strategies.

Identification of HDAC10 as a candidate oncogene in clear cell renal carcinoma that facilitates tumor proliferation and metastasis.

BACKGROUND: Clear cell renal cell carcinoma (ccRCC) remains one of the most lethal urological malignancies even though a great number of improvements in diagnosis and management have achieved over the past few decades. Accumulated evidence revealed that histone deacetylases (HDACs) play vital role in cell proliferation, differentiation and apoptosis. Nevertheless, the biological functions of histone deacetylation modification related genes in ccRCC remains poorly understood. METHOD: Bulk transcriptomic data and clinical information of ccRCC patients were obtained from the TCGA database and collected from the Chinese PLA General Hospital. A total of 36 histone deacetylation genes were selected and studied in our research. Univariate cox regression analysis, least absolute shrinkage and selection operator (LASSO) regression, random forest (RF) analysis, and protein-protein interaction (PPI) network analysis were applied to identify key genes affecting the prognosis of ccRCC. The 'oncoPredict' algorithm was utilized for drug-sensitive analysis. Gene Set Enrichment Analysis (GSEA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was used to explore the potential biological function. The ssGSEA algorithm was used for tumor immune microenvironment analysis. The expression levels of HDAC10 were validated by RT-PCR and immunohistochemistry (IHC). 5-ethynyl-2'-deoxyuridine (EdU assay), CCK-8 assay, cell transwell migration and invasion assay and colony formation assay were performed to detect the proliferation and invasion ability of ccRCC cells. A nomogram incorporating HDAC10 and clinicopathological characteristics was established to predict the prognosis of ccRCC patients. RESULT: Two machine learning algorithms and PPI analysis identified four histone deacetylation genes that have a significant association with the prognosis of ccRCC, with HDAC10 being the key gene among them. HDAC10 is highly expressed in ccRCC and its high expression is associated with poor prognosis for ccRCC patients. Pathway enrichment and the experiments of EdU staining, CCK-8 assay, cell transwell migration and invasion assay and colony formation assay demonstrated that HDAC10 mediated the proliferation and metastasis of ccRCC cells and involved in reshaping the tumor microenvironment (TME) of ccRCC. A clinically reliable prognostic predictive model was established by incorporating HDAC10 and other clinicopathological characteristics ( https://nomogramhdac10.shinyapps.io/HDAC10_Nomogram/ ). CONCLUSION: Our study found the increased expression of HDAC10 was closely associated with poor prognosis of ccRCC patients. HDAC10 showed a pro-tumorigenic effect on ccRCC and promote the proliferation and metastasis of ccRCC, which may provide new light on targeted therapy for ccRCC.

Context-Dependent and Locus-Specific Role of H3K36 Methylation in Transcriptional Regulation.

H3K36 methylation is a critical histone modification involved in transcription regulation. It involves the mono (H3K36me1), di (H3K36me2), and/or tri-methylation (H3K36me3) of lysine 36 on histone H3 by methyltransferases. In yeast, Set2 catalyzes all three methylation states. By contrast, in higher eukaryotes, at least eight methyltransferases catalyze different methylation states, including SETD2 for H3K36me3 and the NSD family for H3K36me2 in vivo. Both Set2 and SETD2 interact with the phosphorylated CTD of RNA Pol II, which links H3K36 methylation to transcription. In yeast, H3K36me3 and H3K36me2 peak at the 3' ends of genes. In higher eukaryotes, this is also true for H3K36me3 but not for H3K36me2, which is enriched at the 5' ends of genes and intergenic regions, suggesting that H3K36me2 and H3K36me3 may play different regulatory roles. Whether H3K36me1 demonstrates preferential distribution remains unclear. H3K36me3 is essential for inhibiting transcription elongation. It also suppresses cryptic transcription by promoting histone deacetylation by the histone deacetylases Rpd3S (yeast) and variant NuRD (higher eukaryotes). H3K36me3 also facilitates DNA methylation by DNMT3B, thereby preventing spurious transcription initiation. H3K36me3 not only represses transcription since it promotes the activation of mRNA and cryptic promoters in response to environmental changes by targeting the histone acetyltransferase NuA3 in yeast. Further research is needed to elucidate the methylation state- and locus-specific functions of H3K36me1 and the mechanisms that regulate it.

A proteasome-dependent inhibition of SIRT-1 by the resveratrol analogue 4,4'-dihydroxy-trans-stilbene.

Background and aim: Resveratrol (RSV), is a stilbene-based compound exerting wide biological properties. Its analogue 4,4'-dihydroxy-trans-stilbene (DHS) has shown improved bioavailability and antiproliferative activity in vitro and in vivo. One of the hypotheses on how resveratrol works is based on SIRT1 activation. Since their strict structural similarities, we have explored a potential interaction between DHS and SIRT1, in comparison with the parental molecule. Experimental procedure: Timing of incubation and concentrations of DHS have been determined using MTT assay in normal human lung fibroblasts. Untreated, DHS- or RSV-treated cells were harvested and analysed by Western Blotting or RT-PCR, in order to evaluate SIRT1 levels/activity and expression, and by Cellular Thermal shift assay (CETSA) to check potential DHS or RSV-SIRT1 interaction. Transfection experiments have been performed with two SIRT1 mutants, based on the potential binding pockets identified by Molecular Docking analysis. Results and conclusion: We unexpectedly found that DHS, but not RSV, exerted a time-dependent inhibitory effect on both SIRT1 protein levels and activity, the latter measured as p53 acetylation. At the mRNA level no significant changes were observed, whereas a proteasome-dependent mechanism was highlighted for the reduction of SIRT1 levels by DHS in experiments performed with the proteasome inhibitor MG132. Bioinformatics analysis suggested a higher affinity of RSV in binding all SIRT1 complexes compared to DHS, except comparable results for complex SIRT1-p53. Nevertheless, both CETSA and SIRT1 mutants transfected in cells did not confirm this interaction. In conclusion, DHS reduces SIRT1 protein level, thereby inhibiting its activity through a proteasome-mediated mechanism.

miR-9-5p regulates Sirt1 involved in testicular development and spermatogenesis in mouse.

Testicular development and spermatogenesis are critical for male reproduction, with histone (de)acetylation playing a key role in chromatin remodeling within germ cells. Sirt1, a key histone deacetylase, is implicated in chromatin remodeling, but its expression pattern and specific role in testicular development and spermatogenesis need further study. This study comprehensively analyzed Sirt1 expression in adult and juvenile mouse testicular tissues and across various male germ cells, utilizing RT-qPCR, Western blot, immunofluorescence, and cell transfection. GO and KEGG enrichment analyses were performed to elucidate the biological functions and pathways associated with Sirt1 and its related genes. Multiple miRNA databases were utilized to predict miRNAs targeting Sirt1, and their expression levels were validated using RT-qPCR. Lentiviral transfection was used to knockdown candidate miRNAs to assess their functional roles. The results revealed a significant downregulation of Sirt1 expression in adult mouse testicular tissues compared to juvenile tissues, with pronounced variation across diverse male germ cells. Sirt1 was highly expressed in spermatogonia and mature sperm, but comparatively lower in spermatocytes and spermatids. GO and KEGG enrichment analyses highlighted Sirt1's role in key biological processes, including chromatin organization, regulation of cell proliferation, and energy homeostasis, as well as its association with signaling pathways like cellular senescence, the FoxO signaling pathway, and the AMPK signaling pathway. Bioinformatic analysis and subsequent RT-qPCR validation identified miR-9-5p as a miRNA targeting Sirt1. The expression of miR-9-5p was significantly higher in adult mouse testicular tissues compared to juvenile tissues, inversely correlating with Sirt1 levels. Moreover, the knockdown of miR-9-5p led to a notable increase in Sirt1 mRNA and protein expression. In conclusion, Sirt1 is a key player in mouse testicular development and spermatogenesis. The discovery that miR-9-5p negatively regulates Sirt1 suggests a critical regulatory axis that may govern these processes, providing novel insights into male fertility and potential targets for therapeutic intervention.

Sirt1 Mitigates Hepatic Lipotoxic Injury Induced by High-Fat-Diet in Fish Through Ire1α Deacetylation.

BACKGROUND: Silent information regulator protein 1 (Sirt1) is crucial in regulating lipid metabolism, but its specific role and mechanism in fish hepatic lipotoxic injury remain undefined. OBJECTIVES: This study aimed to elucidate the regulatory role of Sirt1 and the underlying mechanisms in dietary lipid-induced hepatic lipotoxic injury in a marine teleost black seabream. METHODS: Black seabream were fed a control diet (12% lipid level), high-fat diet (HFD) [18% lipid level, oleic acid (OA)-rich], or HFD supplemented with 0.25%, 0.50%, or 1.00% resveratrol (RSV) for 8 wk. The cultured hepatocytes were stimulated by OA (200 µM), OA supplemented with RSV (20 µM), or transfection with sirt1-small interfering RNA (sisirt1). Biochemical indices, gene expression (qPCR), histology, transmission electron microscope, immunofluorescence, Western blot, flow cytometry, and immunoprecipitation assays were conducted to evaluate hepatic lipid deposition, lipid metabolism, endoplasmic reticulum stress, inflammation and apoptosis, and determine protein interactions between Sirt1 and Ire1α. RESULTS: In vivo, RSV supplementation increased mRNA and protein expression levels of sirt1 (236.2% ± 16.1% and 53.1% ± 14.3%) and downregulated the mRNA and phosphorylated protein expression levels of ire1α/Ire1α (46.0% ± 7.6% and 38.6% ± 7.0%), jnk/Jnk (57.6% ± 7.3% and 122.1%), and nuclear factor κ B (nf-κb/Nf-κb) p65 (41.7% ± 7.1% and 24.6% ± 0.8%) compared with the HFD group. Similar patterns were found in the in vitro experiments; however, after knockdown of sirt1, although the cells were incubated with RSV, the expression levels of ire1α/ Ire1α, jnk/Jnk, and nf-κb/Nf-κb p65 showed no significant differences compared with the OA treatment. Moreover, we found that mutation of K61 to arginine to mimic Ire1α deacetylation confers protection against Ire1α-mediated OA-rich HFD-induced inflammation and apoptosis. CONCLUSIONS: The findings revealed that Sirt1 protects against OA-rich HFD-induced hepatic lipotoxic injury via the deacetylation of Ire1α on K61, hence reducing Ire1α autophosphorylation level, and suppressing Jnk and Nf-κb p65 activation. This mechanism is elucidated for the first time in fish.

Unraveling the multifaceted role of SIRT7 and its therapeutic potential in human diseases.

Sirtuins, as NAD+-dependent deacetylases, are widely found in eubacteria, archaea, and eukaryotes, and they play key roles in regulating cellular functions. Among these, SIRT7 stands out as a member discovered relatively late and studied less extensively. It is localized within the nucleus and displays enzymatic activity as an NAD+-dependent deacetylase, targeting a diverse array of acyl groups. The role of SIRT7 in important cellular processes like gene transcription, cellular metabolism, cellular stress responses, and DNA damage repair has been documented in a number of studies conducted recently. These studies have also highlighted SIRT7's strong correlation with human diseases like aging, cancer, neurological disorders, and cardiovascular diseases. In addition, a variety of inhibitors against SIRT7 have been reported, indicating that targeting SIRT7 may be a promising strategy for inhibiting tumor growth. The purpose of this review is to thoroughly look into the structure and function of SIRT7 and to explore its potential value in clinical applications, offering an essential reference for research in related domains.

Enhanced water and oxygen barrier properties of deacetylated konjac glucomannan/high acyl gellan gum water gradient film for improved frozen fish fillet preservation.

The use of konjac glucomannan (KGM)/high acyl gellan gum (HAGG) edible film with single-sided unsaturated water swelling, designated as a water gradient film (WGF), has been shown to effectively enhance the preservation quality of frozen fish fillets. This study investigates the potential of using partially deacetylated konjac glucomannan (DKGM)/HAGG WGFs to enhance the preservation of frozen fish fillets. The partial deacetylation of KGM improved the water vapour and oxygen barrier properties of the frozen KGM/HAGG WGF, which exhibited a combination of film and ice structural characteristics. This improvement is attributed to strengthened interactions between DKGM and HAGG, resulting in a more structured film matrix that exhibited reduced permeability to both water vapour and oxygen. Furthermore, the improved interactions between DKGM and HAGG led to the formation of smaller polysaccharide ice crystals, which in turn increased the oxygen diffusion path along the intercrystalline boundaries, further decreasing oxygen permeability. Over a 90-day freezing period, the DKGM/HAGG WGF significantly outperformed traditional KGM/HAGG WGF, ice glazing, and polyethylene film packaging in preserving the quality of frozen fish fillets. This study provides a promising strategy for the design and development of DKGM-based WGFs for frozen fish fillet preservation applications.

Impact of konjac glucomannan with varied deacetylation degrees on plant-based meat analogue: Study on the gel properties, digestibility, and microstructure.

Polysaccharides are widely used to improve the quality of plant-based meat analogue (PMA). In this study, four kinds of konjac glucomannan (KG) with different deacetylation degrees (DD) were prepared, namely KG1 (native KG, DD = 0.00 %), KG2 (DD = 41.40 %), KG3 (DD = 80.01 %) and KG4 (DD = 89.07 %), and their effects on the quality of PMA were studied. Results manifested that KG3 improved the hardness (from 3017.16 g to 3307.16 g) and protein digestibility (from 49.65 % to 53.01 %) of PMA without reducing the P21, KG2 and KG4 were less effective than KG3, while KG1 led to a significant decline in the hardness and protein digestibility of PMA. The rheological properties and intermolecular force analysis showed that the partially deacetylated KG was more conducive to improving the G' of the protein system during heating and the proportion of covalent bonds in PMA. These findings suggested that partially deacetylated KG was more promising than native or highly deacetylated KG in PMA. Furthermore, scanning electron microscopy revealed that the morphology of KG gradually changed from fine filaments, to coarse filaments, short filaments and granules as DD increased. This study provides a theoretical basis for the application of partially deacetylated KG in PMA.

SARS-CoV-2 nucleocapsid protein promotes self-deacetylation by inducing HDAC6 to facilitate viral replication.

BACKGROUND: The global outbreak of COVID-19 caused by the SARS-CoV-2 has led to millions of deaths. This unanticipated emergency has prompted virologists across the globe to delve deeper into the intricate dynamicity of the host-virus interface with an aim to identify antiviral targets and elucidate host and viral determinants of severe disease. AIM: The present study was undertaken to analyse the role of histone deacetylase 6 (HDAC6) in regulating SARS-CoV-2 infection. RESULTS: Gradual increase in HDAC6 expression was observed in different SARS-CoV-2-permissive cell lines following SARS-CoV-2 infection. The SARS-CoV-2 nucleocapsid protein (N protein) was identified as the primary viral factor responsible for upregulating HDAC6 expression. Downregulation of HDAC6 using shRNA or a specific inhibitor tubacin resulted in reduced viral replication suggesting proviral role of its deacetylase activity. Further investigations uncovered the interaction of HDAC6 with stress granule protein G3BP1 and N protein during infection. HDAC6-mediated deacetylation of SARS-CoV-2 N protein was found to be crucial for its association with G3BP1. CONCLUSION: This study provides valuable insights into the molecular mechanisms underlying the disruption of cytoplasmic stress granules during SARS-CoV-2 infection and highlights the significance of HDAC6 in the process.

Interplay between DOT1L and HDAC1 regulates Leishmania donovani infection in human THP-1 cells.

Leishmania donovani, a protozoan parasite, causes visceral leishmaniasis. The parasite modifies the global gene expressions of the host genome, facilitating its survival within the host. Thus, the host epigenetic modulators play important roles in host-pathogen interaction and host epigenetic modification in response to infection. Previously, we had reported that the host epigenetic modulator, histone deacetylase 1 (HDAC1) expression was upregulated on Leishmania donovani infection. This upregulation led to the repression of host defensin genes in response to the infection. In this paper, we have investigated the interplay between the host DOT1L, a histone methyltransferase, and HDAC1 in response to Leishmania donovani infection. We show that the expression of DOT1L is upregulated both at transcript and protein level following infection leading to increase in H3K79me, H3K79me2, and H3K79me3 levels. ChIP experiments showed that DOT1L regulated the expression of HDAC1. Downregulation of DOT1L using siRNA resulted in decreased expression of HDAC1 and increased transcription of defensin genes and thereby, lower parasite load. In turn, HDAC1 regulates the expression of DOT1L on Leishmania donovani infection as downregulation of HDAC1 using siRNA led to reduced expression of DOT1L. Thus, during Leishmania donovani infection, an interplay between DOT1L and HDAC1 regulates the expression of these two histone modifiers leading to downregulation of defensin gene expression.

Research Progress on the Mechanism and Function of Histone Acetylation Regulating the Interaction between Pathogenic Fungi and Plant Hosts.

Histone acetylation is a crucial epigenetic modification, one that holds the key to regulating gene expression by meticulously modulating the conformation of chromatin. Most histone acetylation enzymes (HATs) and deacetylation enzymes (HDACs) in fungi were originally discovered in yeast. The functions and mechanisms of HATs and HDACs in yeast that have been documented offer us an excellent entry point for gaining insights into these two types of enzymes. In the interaction between plants and pathogenic fungi, histone acetylation assumes a critical role, governing fungal pathogenicity and plant immunity. This review paper delves deep into the recent advancements in understanding how histone acetylation shapes the interaction between plants and fungi. It explores how this epigenetic modification influences the intricate balance of power between these two kingdoms of life, highlighting the intricate network of interactions and the subtle shifts in these interactions that can lead to either mutual coexistence or hostile confrontation.

Nucleosome remodeler exclusion by histone deacetylation enforces heterochromatic silencing and epigenetic inheritance.

Heterochromatin enforces transcriptional gene silencing and can be epigenetically inherited, but the underlying mechanisms remain unclear. Here, we show that histone deacetylation, a conserved feature of heterochromatin domains, blocks SWI/SNF subfamily remodelers involved in chromatin unraveling, thereby stabilizing modified nucleosomes that preserve gene silencing. Histone hyperacetylation, resulting from either the loss of histone deacetylase (HDAC) activity or the direct targeting of a histone acetyltransferase to heterochromatin, permits remodeler access, leading to silencing defects. The requirement for HDAC in heterochromatin silencing can be bypassed by impeding SWI/SNF activity. Highlighting the crucial role of remodelers, merely targeting SWI/SNF to heterochromatin, even in cells with functional HDAC, increases nucleosome turnover, causing defective gene silencing and compromised epigenetic inheritance. This study elucidates a fundamental mechanism whereby histone hypoacetylation, maintained by high HDAC levels in heterochromatic regions, ensures stable gene silencing and epigenetic inheritance, providing insights into genome regulatory mechanisms relevant to human diseases.

Functionalized chitosan-inspired (nano)materials containing sulfonic acid groups: Synthesis and application.

Nature-inspired chitosan (CS) materials show a high potential for the design/fabrication of sustainable heterogeneous (nano)materials with extraordinary structural/physical features, such as superior biodegradability/biocompatibility, simplicity of chemical modification, environmental safety, high availability, cost-effectiveness, high electrochemical activity, good film-forming ability, and antioxidant, antimicrobial/antibacterial, and anticoagulant activities. Industrialization and growth of industrial wastes or by-products induce an increasing demand for the development of clean, low-cost, and renewable natural systems to minimize or eliminate the utilization of environmentally toxic compounds. The preparation of novel heterogeneous functionalized polysaccharide-inspired bio(nano)materials via chemical modifications of natural CS to improve its physicochemical/biochemical properties has recently become tremendously attractive for many researchers. The most abundantly available and cost-effective functionalized CS-inspired (nano)materials are considerably valuable in terms of the economic aspects of production of (nano)catalysts, (nano)hydrogels, (nano)composite/blend membranes, and thus their commercialization. In this respect, the preparation of functionalized CS-inspired (nano)materials containing -SO3H groups has been represented as a valid alternative to the homogenous unmodified biomaterials for various applications. Sulfonated derivatives of CS-inspired (nano)materials may possess huge surface areas, catalytic activity, adsorption, and biological/biomedical properties. This review article is aimed at the investigation of different methods and potential applications of sulfonated CS-inspired (nano)materials in catalysis, fuel cells, adsorption of ions, membranes, and biological applications.

Epigenetic Cross-Talk Between Sirt1 and Dnmt1 Promotes Axonal Regeneration After Spinal Cord Injury in Zebrafish.

Though spinal cord injury (SCI) causes irreversible sensory and motor impairments in human, adult zebrafish retain the potent regenerative capacity by injury-induced proliferation of central nervous system (CNS)-resident progenitor cells to develop new functional neurons at the lesion site. The hallmark of SCI in zebrafish lies in a series of changes in the epigenetic landscape, specifically DNA methylation and histone modifications. Decoding the post-SCI epigenetic modifications is therefore critical for the development of therapeutic remedies that boost SCI recovery process. Here, we have studied on Sirtuin1 (Sirt1), a non-classical histone deacetylase that potentially plays a critical role in neural progenitor cells (NPC) proliferation and axonal regrowth following SCI in zebrafish. We investigated the role of Sirt1 in NPC proliferation and axonal regrowth in response to injury in the regenerating spinal cord and found that Sirt1 is involved in the induction of NPC proliferation along with glial bridging during spinal cord regeneration. We also demonstrate that Sirt1 plays a pivotal role in regulating the HIPPO pathway through deacetylation-mediated inactivation of Dnmt1 and subsequent hypomethylation of yap1 promoter, leading to the induction of ctgfa expression, which drives the NPC proliferation and axonal regrowth to complete the regenerative process. In conclusion, our study reveals a novel cross-talk between two important epigenetic effectors, Sirt1 and Dnmt1, in the context of spinal cord regeneration, establishing a previously undisclosed relation between Sirt1 and Yap1 which provides a deeper understanding of the underlying mechanisms governing injury-induced NPC proliferation and axonal regrowth. Therefore, we have identified Sirt1 as a novel, major epigenetic regulator of spinal cord regeneration by modulating the HIPPO pathway in zebrafish.