H3K9ac Levels Research Articles

Direct and Indirect Protein Interactions Link FUS Aggregation to Histone Post-Translational Modification Dysregulation and Growth Suppression in an ALS/FTD Yeast Model

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are incurable neurodegenerative disorders sharing pathological and genetic features, including mutations in the FUS gene. FUS is an RNA-binding protein that mislocalizes to the cytoplasm and aggregates in ALS/FTD. In a yeast model, FUS proteinopathy is connected to changes in the epigenome, including reductions in the levels of H3S10ph, H3K14ac, and H3K56ac. Exploiting the same model, we reveal novel connections between FUS aggregation and epigenetic dysregulation. We show that the histone-modifying enzymes Ipl1 and Rtt109—responsible for installing H3S10ph and H3K56ac—are excluded from the nucleus in the context of FUS proteinopathy. Furthermore, we found that Ipl1 colocalizes with FUS, but does not bind it directly. We identified Nop1 and Rrp5, a histone methyltransferase and rRNA biogenesis protein, respectively, as FUS binding partners involved in the growth suppression phenotype connected to FUS proteinopathy. We propose that the nuclear exclusion of Ipl1 through indirect interaction with FUS drives the dysregulation of H3S10ph as well as H3K14ac via crosstalk. We found that the knockdown of Nop1 interferes with these processes. In a parallel mechanism, Rtt109 mislocalization results in reduced levels of H3K56ac. Our results highlight the contribution of epigenetic mechanisms to ALS/FTD and identify novel targets for possible therapeutic intervention.

The Role of H3K27 acetylation in oxygen-glucose deprivation-induced spinal cord injury and potential for neuroprotective therapies

ObjectiveSpinal cord injury (SCI) is a debilitating condition that often results in paralysis and lifelong medical challenges. Research has shown that epigenetic modifications, particularly histone acetylation, play a role in neuroprotection following hypoxic-ischemic events in SCI. The objective of this study was to explore the effects of histone H3K27 acetylation, along with its underlying mechanisms, on the tolerance to hypoxia and ischemia in SCI. MethodsThis study employed an organotypic spinal cord slice culture model subjected to oxygen-glucose deprivation (OGD). We assessed cell apoptosis and changes in cellular type patterns under these conditions. Following hypoxia and ischemia, we analyzed the expression and distribution of H3K27ac across various nerve cell types. To identify key downstream genes, we integrated ChIP-seq and RNA-seq analyses, investigating molecular mechanisms driving the response to OGD in this model. ResultsOGD stimulation increased cell apoptosis and induced time-dependent changes in the expression patterns of neurons, astrocytes, microglia, and oligodendrocytes in organotypic spinal cord slices, accompanied by a significant reduction in H3K27ac levels. Integrated ChIP-seq and RNA-seq analyses revealed that H3K27ac downregulation under hypoxic and ischemic conditions contributes to spinal cord damage by promoting neuroinflammation and disrupting gene regulation. Furthermore, we identified key downstream targets, including Apoc1, Spp1, Aff1, Brd4, KCNN3, and Rgma, which may represent promising therapeutic targets for SCI. ConclusionOur data underscore the pivotal role of H3K27ac in the organotypic spinal cord slice culture model following OGD exposure, offering promising avenues for neuroprotective therapies via epigenetic-immune regulation.

BPZ inhibits early mouse embryonic development by disrupting maternal-to-zygotic transition and mitochondrial function.

The use of Bisphenol A (BPA) has been widely restricted due to its adverse health effects. Bisphenol Z (BPZ) is used as an alternative to BPA, and humans are widely exposed to BPZ through various routes. Recent studies have shown that BPZ exposure adversely affects mouse oocyte meiotic maturation. This study investigates the impact of BPZ exposure on early mouse embryonic development alongside an exploration of the underlying mechanisms. The findings reveal that exposure to BPZ leads to a reduction in early embryo quality and hinders developmental progression. RNA sequencing analysis has identified 593 differentially expressed genes as a result of BPZ exposure, highlighting considerable changes in early embryonic gene expression. Mechanistically, BPZ exposure inhibits the activation of the zygotic genome and impedes maternal mRNA degradation, thereby interfering with maternal-to-zygotic transition (MZT). Further analysis indicates compromised mitochondrial function, as evidenced by abnormal distribution, diminished membrane potential, and lower ATP levels. Consequently, BPZ-exposed embryos exhibit elevated levels of reactive oxygen species, superoxide anions, and oxidative DNA damage. Moreover, BPZ exposure is associated with an increase in γ-H2A.X expression. Additionally, BPZ exposure alters the expression levels of histone modifications, including H3K27me2, H3K27me3, H3K9me3, and H3K27ac, in early embryos. Collectively, BPZ exposure significantly impairs early embryo quality by disrupting mitochondrial function, inducing oxidative stress and DNA damage, altering histone modifications, and inhibiting MZT, ultimately resulting in hindered blastocyst formation. These findings underscore the profound adverse effects of BPZ on early embryonic development, indicating the need for caution when considering it as a safe alternative to BPA.

SEMA3C promotes thyroid cancer via the Wnt/β-catenin pathway.

Semaphorin 3C (SEMA3C) regulates the progression of several tumors. However, the role of SEMA3C in thyroid cancer remains unknow. In the present study, SEMA3C was overexpressed or knocked down in thyroid cancer cell lines BCPAP and IHH-4. It was found that SEMA3C promoted the cell migration, invasion, and mesenchymal-epithelial transition (EMT) process. SEMA3C overexpression enhanced tumor cell stemness, while SEMA3C knockdown showed the opposite effects. In vivo experiments suggested that SEMA3C accelerated the tumor growth and metastasis. Moreover, SEMA3C enhanced β-catenin nuclear translocation. When cells were treated with Dickkopf-1 (DKK1), an inhibitor of Wnt/β-catenin pathway, the promoting effects of SEMA3C on cell migration and stemness were offset. Wnt/β-catenin pathway mediated the roles of SEMA3C in thyroid cancer. Additionally, an upstream regulator of SEMA3C was identified. E1A binding protein P300 (P300) was found to increase the histone three lysine 27 acetylation (H3K27ac) level of SEMA3C, promoting its transcriptional activation. Therefore, we clarify that SEMA3C exerts a tumor-promoting effect on thyroid cancer, and Wnt/β-catenin pathway is the critical downstream pathway.

Angong Niuhuang Pill pretreatment alleviates cerebral ischemia-reperfusion injury by inhibiting excessive autophagy through the SIRT1-H4K16ac axis

Ethnopharmacological relevanceCerebral ischemia-reperfusion injury (CIRI) is an important pathological process in stroke treatment. Angong Niuhuang Pill (ANP), originating from Wenbing Tiaobian, has been shown to have neuroprotective effects, but its mechanism in alleviating CIRI remains unclear. Aim of the studyThis study aimed to elucidate the mechanism by which ANP alleviates CIRI using acetylomics and proteomics. Materials and methodsThe CIRI model was established using middle cerebral artery occlusion (MCAO). Neurological deficit scoring, TTC staining, regional cerebral blood flow (rCBF) measurement, and TUNEL staining were used to assess the neuroprotective effects of ANP pretreatment on CIRI. Acetylomics and proteomics analyses were performed to identify the potential mechanisms by which ANP reduces CIRI. Finally, the role of SIRT1-H4K16ac-mediated autophagy in the neuroprotective effects of ANP was validated by using a SIRT1 inhibitor, EX527. ResultsANP pretreatment markedly lowered neurological deficit scores and cerebral infarct volumes, increased rCBF, and reduced apoptosis. Acetylomics and proteomics results suggested that ANP regulated autophagy at the transcriptional level by modulating H4K16ac. Immunofluorescence and western blot analyses confirmed that ANP promoted the accumulation of sirtuin 1 (SIRT1). Specifically, ANP pretreatment reduced H4K16ac levels, decreased LC3B-II/I ratios, upregulated SQSTM1/p62, and suppressed the expression of ATG5 and ATG7. The ability of EX527 to counteract these effects underscored the importance of the SIRT1-H4K16ac pathway in mediating the protective action of ANP against CIRI. ConclusionsANP provides neuroprotection by modulating the SIRT1-H4K16ac pathway, thereby preventing the excessive autophagy triggered by CIRI.

Metastasis-associated lung adenocarcinoma transcript 1 overexpression in testis contributes to idiopathic non-obstructive azoospermia via repressing ETS variant transcription factor 5.

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), is a long non-coding RNA localized in the cell nucleus, known for its multifunctional roles, including potential involvement in spermatogenesis. This study investigates the mechanism by which MALAT1 dysregulation contributes to the pathogenesis of idiopathic non-obstructive azoospermia (iNOA). We analyzed MALAT1 levels in two gene expression profiling datasets comprising patients with obstructive azoospermia (OA) who have normal spermatogenesis and 13 patients with iNOA. The dysregulation of MALAT1 along with the expression levels of its negatively correlated genes were confirmed in a larger cohort of 24 OA patients and 38 iNOA patients. We examined the effects of MALAT1 overexpression in primary human spermatogonial stem cells (SSCs) and Sertoli cells. Additionally, we assessed DNA methylation, as well as levels of H3K27me3 and H3K27Ac level near the etv5 promoter region using ChIP-qPCR. We observed that MALAT1 was overexpressed in testes of iNOA patients with its levels negatively correlating with six spermatogenesis related genes and positively correlated with three others. Overexpression of MALAT1 in SSCs repressed proliferation and induced apoptosis while also suppressing ETS variant transcription factor 5 (ETV5) expression by promoting H3K27 tri-methylation of the ETV5 promoter. Overexpression of MALAT1 in Sertoli cells did not induce apoptosis but impaired their cell supporting function. In conclusion, MALAT1 overexpression in SSCs contributes to the pathogenesis of iNOA via downregulating ETV5 expression and promoting cell apoptosis.

The Lyn/RUVBL1 Complex Promotes Colorectal Cancer Liver Metastasis by Regulating Arachidonic Acid Metabolism Through Chromatin Remodeling.

Liver metastasis is a common cause of death in colorectal cancer (CRC) patients, but epigenetic remodeling and metabolic reprogramming for CRC liver metastasis remain unclear. The study revealed that the Lyn/RUVBL1 complex is highly expressed in CRC and is closely correlated with liver metastasis. On the one hand, ATAC-seq and HiCut suggested that Lyn/RUVBL1 regulates the expression of TRIB3 through the POL II-mediated chromatin conformation of TRIB3 and thus the expression of β-catenin. This promotes the proliferation and migration of CRC through β-catenin-mediated upregulation of MMP9 and VEGF. On the other hand, metabolomics revealed that Lyn/RUVBL1 regulates the expression of PGE2 through the enzyme COX2, thereby promoting arachidonic acid (AA) metabolism. CUT-Tag showed that Lyn/RUVBL1 silencing reduces the H3K27ac level in the COX2 promoter. Then, it is found that COX2 is regulated by the transcription factor FOXA1. Lyn/RUVBL1 modulates AA metabolism by regulating the chromatin accessibility of FOXA1. AA metabolism promotes the metastasis of CRC by affecting β-catenin nuclear translocation and upregulating MMP9 and VEGF. These findings suggest that the Lyn/RUVBL1 complex mediates epigenetic remodeling to regulate the metabolic reprogramming of AA, highlighting its role in promoting the metastasis of CRC.

Engineering FRET biosensor for H3K9 acetylation imaging in single living cells

Histone acetylation is an important epigenetic modification that governs gene expression, chromatin changes in stress response, and cell fate transition. FRET biosensors have been developed for various epigenetic events to enable spatiotemporal tracking of sub-cellular signaling events. Previously reported histone H3 acetylation biosensor recognizing two acetyl residues lacked specificity. In this study, using a single bromodomain of the BRD4, we have developed a genetically encoded H3K9ac biosensor. We systematically investigated different combinations of the BET family protein as binding domains and performed site-saturated mutagenesis to optimize the biosensor, achieving a dynamic FRET change up to 30% under TSA treatment. With the application of the optimized H3K9ac biosensor, we revealed different basal active chromatin architectures in invasive tumor cells compared to benign tumor cells. Furthermore, we found that H3K9ac level increased dramatically when cancer cells passed through microchannels, which models the physical constraints and mechanical microenvironmental conditions that cancer cells encounter when passing through narrow spaces within the body. This result highlights the chromatin plasticity in response to external mechanical stresses. In summary, our H3K9ac biosensor provides a versatile tool for mechanistic investigation of cell fate transition in cancer and mechanotransduction.Graphical

Energy Stress-induced CircEPB41(2) Promotes Lipogenesis in Hepatocellular Carcinoma.

The tumor microenvironment plays a pivotal role in the metabolic reprogramming of cancer cells. A better understanding of the underlying mechanisms regulating cancer metabolism could help identify potential therapeutic targets. Here, we identified circEPB41(2) as a metabolically regulated circular RNA that mediates lipid metabolism in hepatocellular carcinoma (HCC). CircEPB41(2) was induced in response to glucose deprivation via HNRNPA1-dependent alternative splicing. Upregulation of circEPB41(2) led to enhanced lipogenic gene expression that promoted lipogenesis. Mechanistically, circEPB41(2) cooperated with the m6A demethylase FTO to decrease the mRNA stability of the histone deacetylase SIRT6, thereby increasing H3K9ac and H3K27ac levels to activate lipogenic gene expression. Silencing of circEPB41(2) inhibited both in vitro proliferation of HCC cells and in vivo growth of tumor xenografts. Clinically, circEPB41(2) was elevated in HCC, and high circEPB41(2) expression was associated with poor patient prognosis. Overall, this study reveals that circEPB41(2) is an important regulator of lipid metabolic reprogramming and indicates that targeting the circEPB41(2)-FTO-SIRT6 axis could represent a promising anti-cancer strategy for treating HCC.

APN/AdipoRon regulates luteal steroidogenesis through AMPK/EZH2/H3K27me3 in goats.

AMPK plays a crucial role in cellular energy metabolism and is involved in the regulation of luteal steroidogenesis by APN and its analog AdipoRon. To further explore the regulatory mechanism of AMPK in goat luteal steroidogenesis mediated by APN, cyclic and pregnant CL were utilized to assess the localization and expression of AMPK, EZH2, H3K27me3 and H3K27ac by WB and mIHC, and the interaction between AMPK and EZH2 by Co-IP. Then, isolated luteal cells were treated with APN/AdipoRon to evaluate the expression levels of AMPK, EZH2, H3K27me3 and H3K27ac. Results showed that AMPK and EZH2 were co-localized to the cytoplasm of luteal cells, and interacted as detected by Co-IP. H3K27me3 and H3K27ac were localized to the nucleus of goat luteal cells. H3K27me3 expression in late CL was significantly higher than that in early and middle CL, while the expressions of AMPK, H3K27ac and EZH2 in middle CL were significantly higher than those in early and late CL. Notably, all these proteins were expressed at similar levels between pregnancy and middle cycle, with the exception of EZH2. Following incubation with AdipoRon (25 μM) and APN (1 μg/mL) for 24 h, the expressions of AMPK and H3K27ac decreased, while H3K27me3 increased in luteal cells. Compound C (AMPK activity inhibitor) reversed the AdipoRon - induced decrease in EZH2 expression and the increase in H3K27me3 expression. The increased H3K27me3 expression and decreased steroidogenic protein (CYP11A1 and HSD3B) expression after GSK126 (EZH2 inhibitor) treatment were consistent with the effects seen after AdipoRon treatment. In conclusion, APN/AdipoRon inhibits luteal steroidogenesis by inhibiting the interaction between AMPK and EZH2, thereby promoting H3K27me3 expression.

GNAO1 overexpression promotes neural differentiation of glioma stem-like cells and reduces tumorigenicity through TRIM21/CREB/HES1 axis.

Inducing tumor cell differentiation is a promising strategy for treating malignant cancers, including glioma, yet the critical regulator(s) underlying glioma cell differentiation is poorly understood. Here, we identify G Protein Subunit Alpha O1 (GNAO1) as a critical regulator of neural differentiation of glioma stem-like cells (GSCs). GNAO1 expression was lower in gliomas than in normal neuronal tissues and high expression of GNAO1 correlated with a better prognosis. GNAO1 overexpression markedly promoted neural differentiation of GSCs, leading to decreased cell proliferation and colony formation. Mechanistically, GNAO1 recruited TRIM21 and facilitated TRIM21-mediated ubiquitination. This ubiquitination resulted in the degradation of CREB and further reduced p300-mediated H3K27ac levels of the HES1 promoter. As a result, GNAO1 overexpression downregulated HES1 expression, which reinforced neuronal differentiation. In addition, knockdown of METTL3, a key writer of the N6-methyladenosine (m6A), enhanced GNAO1 mRNA stability. Treatment with GNAO1 adenovirus increased neuronal differentiation of tumor cells and reduced tumor cell proliferation in orthotopic GSC xenografts and temozolomide further enhanced GNAO1 adenovirus effects, resulting in extended animal survival. Our study presents that engineering GNAO1 overexpression-inducing neural differentiation of GSCs is a potential therapy strategy via synergistic inhibition of malignant proliferation and chemotherapy resistance.

Imatinib Impedes EMT and Notch Signalling by Inhibiting p300 Acetyltransferase in Breast Cancer Cells.

Breast cancer remains a leading cause of cancer-related mortality among women, with current therapeutic approaches often limited by resistance and recurrence, especially in aggressive subtypes like triple-negative breast cancer. Drug repurposing has emerged as a promising strategy to address these challenges. In this study, we investigate the potential of Imatinib, a repurposed tyrosine kinase inhibitor, to inhibit epithelial-mesenchymal transition (EMT) in breast cancer cells by modulating the Notch signalling pathway. Our findings reveal that Imatinib treatment leads to a significant reduction in cancer cell stemness, invasiveness, and migration potential, alongside decreased colony-forming ability. EMT reversal was marked by a 2.71-fold increase in E-cadherin expression, with concurrent downregulation of mesenchymal markers, including Fibronectin (1.78-fold) and Slug (2.15-fold). Mechanistically, Imatinib was found to inhibit p300 acetyltransferase activity, resulting in reduced levels of H3K18Ac and H3K27Ac, which in turn led to the downregulation of key Notch pathway proteins such as HES1 (2.94-fold), AKT (2.08-fold), and p21 (1.88-fold). These results highlight the ability of Imatinib to suppress EMT through modulation of the Notch signalling pathway, offering a novel therapeutic avenue for breast cancer treatment. Overall, Imatinib demonstrates considerable potential for repurposing in breast cancer management by targeting critical oncogenic pathways involved in EMT and cancer progression.

β-Caryophyllene oxide inhibits lysine acetylation of histones in Fusarium proliferatum to block ribosomal biosynthesis and function

The natural bicyclic sesquiterpene, β-Caryophyllene oxide (BCPO), has demonstrated inhibitory activity against Fusarium species. While previous studies have documented its antifungal properties through various biochemical mechanisms, the role of BCPO in modulating epigenetic modifications of DNA via histone deacetylases (HDACs) has received comparatively less attention. The study aims to elucidate how BCPO inhibits Fusarium proliferatum by affecting histone acetylation. Our results indicate that BCPO enhances FPRO_01165 (FpSIR2) enzyme activity to 6.01 ng/min/mg, representing a 55.30 % increase. Molecular docking analysis and molecular dynamics simulation confirmed the interaction between BCPO and FpSIR2. Furthermore, high concentrations (HC) of BCPO significantly inhibited the growth of F. proliferatum, resulting in marked reductions in H3K9ac and H3K27ac modification levels. We conducted chromatin immunoprecipitation sequencing (ChIP-seq) to identify enrichments of H3K9ac and H3K27ac, while also obtaining transcriptomic data from the HC treatment group. Combined analyses revealed that decreased levels of H3K9ac and H3K27ac primarily affected ribosomal pathways in F. proliferatum, leading to downregulation of several ribosomal genes and their corresponding proteins, such as RPL4, RPS19, and RPS16. Our findings suggest that BCPO stimulates both the production and activity of FpSIR2, which subsequently inhibits histone lysine acetylation in F. proliferatum. This inhibition suppresses ribosome biosynthesis and function as well as overall growth in this pathogen. The property of BCPO to reduce acetylation provides new insights for developing highly efficient yet low-toxicity antifungal agents.

Identification of novel transcription factors regulated by H3K27 acetylation in myogenic differentiation of porcine skeletal muscle satellite cells.

H3K27 acetylation (H3K27ac) is crucial in muscle development as it regulates gene expression. Dysregulation of H3K27ac level has been linked to muscle-related diseases such as Duchenne muscular dystrophy, yet the mechanisms through which H3K27ac influences myogenic differentiation are not fully understood. Here, we utilized the SGC-CBP30 drug, a CBP/p300 bromodomain inhibitor, to reduce H3K27ac level and investigated its effect on myogenic differentiation of porcine skeletal muscle satellite cells. The results demonstrated an increased H3K27ac level during normal muscle satellite cell differentiation. We found that the addition of SGC-CBP30 resulted in a reduced level of H3K27ac based on ATAC-seq and CUT&Tag data. Our analysis revealed that a cluster characterized by reduced levels of H3K27ac and increased levels of H3K27me3 was enriched with motifs corresponding to Bach2, MafK, and Fosl2 transcription factors. Furthermore, knockdown of Bach2, MafK, and Fosl2 produced a similar suppression effect on myogenic differentiation. Taken together, our study contributes to a better understanding of how H3K27ac influences myogenic differentiation.

Histone-acetyl epigenome regulates TGF-β pathway-associated chemoresistance in colorectal cancer

TGF-β signaling pathway has been demonstrated to be closely related to chemoresistance, which is the major cause of recurrence and poor outcome in colorectal cancer (CRC), however, the comprehensive epigenetic landscape that functionally implicates in the regulation of TGF-β pathway-associated chemoresistance has not yet well established in CRC. In our study, chromatin immunoprecipitation sequencing (ChIP-seq) and Western blot were employed to investigate epigenetic modifications for histones in response to TGF-β1 intervene. We found that the activation of the TGF-β pathway was characterized by genome-wide high levels of H3K9ac and H3K18ac. Mechanistically, the activation of the TGF-β signaling pathway leads to the downregulation of the deacetylase HDAC4, resulting in the upregulation of H3K9ac and H3K18ac. Consequently, this cascade induces oxaliplatin chemoresistance in CRC by triggering the anti-apoptotic PI3K/AKT signaling pathway. Our in vivo experiment results confirmed that overexpression of HDAC4 significantly enhances the sensitivity of CRC to oxaliplatin chemotherapy. Moreover, the expression level of HDAC4 was positively correlated with patients’ prognosis in CRC. Our data suggest that histone-acetyl modification demonstrates a crucial role in modulating TGF-β pathway-associated chemoresistance in CRC, and HDAC4 would be a biomarker for prognostic prediction and potential therapeutic target for treatment in CRC.

Inhibition of cytokine-like protein 1 transcription hinders wound-healing process in diabetic rats.

This study explored the function and mechanism of cytokine-like protein 1 (CYTL1) in regulating the wound-healing process of rats with diabetes mellitus (DM). A wound was made in diabetic rats, in which CYTL1 overexpression or HDAC1 expression-interfering adenovirus was injected. The wound area on day 0, 7, 14 and 21 was observed and photographed to calculate the wound-healing rate. The wound tissues were collected for H&E, Masson staining and CD31 immunohistochemistry. The HDAC1 and CYTL1 mRNA and protein expressions in wound tissues were detected by RT-qPCR and western blot. The regulation of HDAC1 on CYTL1 was predicted by hTFtarget and AnimalTFDB database. The H3K27Ac level in the CYTL1 promoter was detected by chromatin immunoprecipitation (ChIP). Diabetic rats with CYTL1 overexpression or interfered HDAC1 expression had accelerated the wound-healing rate, in which massive fibroblasts, attenuated inflammatory infiltration and increased collagen and microvessel density were observed. Further experiments found that HDAC1 can inhibit CYTL1 transcription and expression by inhibiting H3K27Ac expression in CYTL1 promoter. Collected evidence showed HDAC1 can inhibit CYTL1 transcription by down-regulating the H3K27Ac level in CYTL1 promoter to slow down the wound-healing process in diabetic ulcer rats.

ITreg cells-secreted IL10 alleviates lupus nephritis through inactivating lncRNA HAR1A transcription to suppress SMARCD1-mediated iNOS activation

Lupus nephritis (LN) is a highly prevalent complication of systemic lupus erythematosus (SLE). Long non-coding RNAs (lncRNAs) are essential modulators in multiple types of human diseases, including LN. In the current study, we searched on online GEO database to select out lncRNAs that were differentially expressed in blood samples of LN patients. Through further RT-qPCR analysis, we found that lncRNA Highly Accelerated Region 1 A (HAR1A) is most significantly upregulated in blood samples of LN patients. Functionally, we detected that overexpression of HAR1A could aggravate LPS-induced injury and inflammation. According to the results of bioinformatics analysis and mechanism experiments, we determined that HAR1A binds with miR-149-3p to upregulate SMARCD1 through competing endogenous RNA (ceRNA) mechanism. It has been proven that iNOS is an inflammation inducer. Here, we found that HAR1A/miR-149-3p/SMARCD1 upregulates iNOS expression through enhancing H3K27ac level in iNOS promoter. Previously, we proved that CD8+CD103+ iTreg cells could alleviate glomerular endothelial cell injury. Moreover, we demonstrated that CD8 + CD103+ iTreg cells-secreted IL-10 downregulated HAR1A expression by impeding NF-κB pathway activation. In conclusion, this study provides evidences revealing a novel molecular pathway blocked by CD8+CD103+ iTreg cells in LN.

Damascenone inhibits osteoclastogenesis by epigenetically modulating Nrf2-mediated ROS scavenge and counteracts OVX-induced osteoporosis

BackgroundBone formation and resorption regulate bone homeostasis. Excessive osteoclastogenesis enhances bone resorption and causes osteoporosis. Although medicines targeting osteoclast have been developed, these drugs have several side effects. Natural compounds have advantages in safety and efficiency, making them potential candidates for osteoporosis treatment. PurposeThis study aims to elucidate the role of damascenone (Dama) in osteoclastogenesis and osteoporosis. Study design and methodsTo demonstrate the effect of Dama on osteoclast differentiation and function, we performed multiple in vitro experiments including TRAP staining, F-actin staining, bone slice resorption assay, real-time PCR, and western bolt. Further, ROS detection, network pharmacology, microscale thermophoresis assay, and ChIP assay were conducted to elucidate the underlying molecular mechanism. Finally, the in vivo effects of Dama were verified using an ovariectomy induced osteoporosis mice model. ResultsDama inhibited RANKL-induced osteoclast differentiation and bone resorptive function in vitro. The expression of osteoclast-related genes and activation of MAPKs and NF-κB signaling in osteoclast were also attenuated by Dama. Meanwhile, Dama reduced intracellular ROS level via up-regulating Nrf2 expression. Network pharmacology demonstrated that HDAC2 is the potential direct target of Dama. Dama inhibited HDAC2 function and increased H3K27ac level of Nrf2, which induced Nrf2 expression and activated ROS scavenging enzymes. Inhibiting NRF2 or activating HDAC2 attenuated the effect of Dama on osteoclastogenesis. Finally, Dama injection suppressed in vivo osteoclastogenesis and ameliorated bone loss induced by OVX. ConclusionDama attenuates osteoclastogenesis by epigenetically modulating Nrf2 expression and ROS scavenge. This study provides evidence for Dama being a potential treatment for osteoporosis.

New epigenome players in the regulation of PCSK9-H3K4me3 and H3K9ac alteration by statins in hypercholesterolemia

Statins are the most effective drugs used worldwide to lower the serum LDL-C by inhibiting the rate-limiting step, HMG-CoA reductase, in cholesterol biosynthesis. Despite its prevalent use, statins are known to increase proprotein convertase subtilisin/kexin type 9 (PCSK9) expression, hindering its efficiency. However, the underlying mechanisms remain elusive. In this study, we have unraveled the pleiotropic effects of statins on hypercholesterolemia via epigenetic regulation of PCSK9. We observed that atorvastatin (ATS) increases the fold enrichment of H3K4me3 at the promoter of PCSK9 by elevating the expression of the SET1/COMPASS family of proteins like SET1b and MLL1 in HepG2. In addition, ATS also acetylates H3K9 by increasing the expression of acetyltransferases like CBP and PCAF. Similarly, in mice fed a high-fat diet, ATS showed increased levels of H3K4me3 and H3K9ac in the liver. Furthermore, a pharmacological intervention that inhibits the H3K4me3 and H3K9ac enrichment resulted in the reversal of statin-induced upregulation of PCSK9. Combining statin and OICR-9429 or resveratrol improved the overall uptake of LDL by hepatocytes. Together, these findings suggest that statin induces the colocalization of H3K4me3 and H3K9ac to transcribe PCSK9 actively and that inhibiting these marks reduces PCSK9 expression and ultimately increases hepatocyte LDL uptake. Our study unveils a previously unknown epigenetic mechanism of PCSK9 regulation that may lead to statin resistance or futility in patients and provide a potential therapeutic solution.

Conserved helical motifs in the IKZF1 disordered region mediate NuRD interaction and transcriptional repression

AbstractThe transcription factor (TF) Ikaros zinc finger 1 (IKZF1) is essential for B-cell development, and recurrently mutated in human B-cell acute lymphoblastic leukemia (B-ALL). IKZF1 has been ascribed both activating and repressive functions via interactions with coactivator and corepressor complexes, but the relative abundance of IKZF1-associated coregulators and their contribution to IKZF1-mediated gene regulation are not well understood. To address this, we performed an unbiased identification of IKZF1-interacting proteins in pre-B cells and found that IKZF1 interacts overwhelmingly with corepressors and heterochromatin-associated proteins. Time-resolved analysis of transcription and chromatin state identified transcriptional repression as the immediate response to IKZF1 induction. Transcriptional repression preceded transcriptional activation by several hours, manifesting as a decrease in the fraction of transcriptional bursts at the single-molecule level. Repression was accompanied by a rapid loss of chromatin accessibility and reduced levels of H3K27ac, particularly at enhancers. We identified highly conserved helical motifs within the intrinsically disordered region of IKZF1 that mediate its association with the nucleosome remodeling and deacetylase (NuRD) corepressor complex through critical “KRK” residues that bind the NuRD subunit RBBP4, a mechanism shared with the TFs FOG1, BCL11A, and SALL4. Functional characterization reveals that this region is necessary for the efficient silencing of target genes and antiproliferative functions of IKZF1 in B-ALL.