Huanglian-Jiedu decoction promotes adipose thermogenesis in obese mice by suppressing the expression of HDAC3.

ETHNOPHARMACOLOGICAL RELEVANCE: Huanglian Jiedu Decoction (HLJDD) is an ancient formula of traditional Chinese medicine that is commonly utilized in a range of disorders, and it has been shown to have pharmacological effects on glucose and lipid metabolism. However, the specific mechanism of HLJDD for the treatment of obesity and related metabolic disorders remains to be further investigated. AIM OF THE STUDY: It has been thought that encouraging adipose thermogenesis to raise the body's energy expenditure is a useful tactic for improving metabolic abnormalities and losing weight. In this study, we investigated the ability and underlying mechanisms of HLJDD to regulate fat cell thermogenesis to improve energy expenditure in obesity. METHODS: The obese mouse model was established on a high-fat diet for 12 weeks. All mice were divided into NC, HFD, HFD with HLJDD of a low dose (2.25 g/kg/d), and HFD with HLJDD of a high dose (4.5 g/kg/d) groups and kept for 4 weeks. In vitro experiments were conducted to evaluate the effects of 5% and 10% HLJDD-containing serum on differentiated 3T3-L1 cells and HDAC3-knocking-down 3T3-L1 cells. RESULTS: The results showed that HLJDD treatment significantly improved glucose and insulin tolerance and decreased the adipocyte radius of WATs, as well as increased energy consumption in obese mice. Besides, HLJDD treatment dramatically increased the levels of thermogenic genes UCP-1 and PGC-1α while suppressing HDAC3 levels in WATs and 3T3-L1 adipocytes. Importantly, the effects of HLJDD on PGC-1α and UCP-1 were blocked in HDAC3 knockdown adipocytes. CONCLUSIONS: Therefore, these results suggest that HLJDD enhanced adipose thermogenesis and improved energy expenditure by inhibiting HDAC3, thereby increasing UCP-1 and PGC-1α expression. These findings amplified the mechanisms of HLJDD and its potential to treat obesity and related metabolic disorders.

The identification of potent dual-target monopolar spindle 1 (MPS1) and histone deacetylase 8 (HDAC8) inhibitors through pharmacophore modeling, molecular docking, molecular dynamics simulations, and biological evaluation.

Background: Overexpression of monopolar spindle 1 (MPS1) and histone deacetylase 8 (HDAC8) is associated with the proliferation of liver cancer cells, so simultaneous inhibition of both MPS1 and HDAC8 could offer a promising therapeutic approach for the treatment of liver cancer. Dual-targeted MPS1/HDAC8 inhibitors have not been reported. Methods: A combined approach of pharmacophore modeling and molecular docking was used to identify potent dual-target inhibitors of MPS1 and HDAC8. Enzyme inhibition assays were performed to evaluate the optimal compound with the strongest inhibitory activity against MPS1 and HDAC8. The selectivity of MPH-5 for MPS1 and HDAC8 was assessed on a panel of 68 kinases and other histone deacetylases. Subsequently, molecular dynamics (MD) simulation verified the binding stability of the optimal compound to MPS1 and HDAC8. Ultimately, in vitro cellular assays and in vivo antitumor assays evaluated the antitumor efficacy of the most promising compound for the treatment of hepatocellular carcinoma. Results: Six dual-target compounds (MPHs 1-6) of both MPS1 and HDAC8 were identified from the database using a combined virtual screening protocol. Notably, MPH-5 showed nanomolar inhibitory effect on both MPS1 (IC50 = 4.52 ± 0.21 nM) and HDAC8 (IC50 = 6.07 ± 0.37 nM). MD simulation indicated that MPH-5 stably binds to both MPS1 and HDAC8. Importantly, cellular assays revealed that MPH-5 exhibited significant antiproliferative activity against human liver cancer cells, especially HepG2 cells. Moreover, MPH-5 exhibited low toxicity and high efficacy against tumor cells, and it overcomes drug resistance to some extent. In addition, MPH-5 may exert its antitumor effects by downregulating MPS1-driven phosphorylation of histone H3 and upregulating HDAC8-mediated K62 acetylation of PKM2. Furthermore, MPH-5 showed potent inhibition of HepG2 xenograft tumor growth in mice with no apparent toxicity and presented favorable pharmacokinetics. Conclusion: The study suggests that MPH-5 is a potent, selective, high-efficacy, and low-toxicity antitumor candidate for the treatment of hepatocellular carcinoma.

ZNF521 promotes acute myeloid leukemogenesis by suppressing the expression and acetylation of SMC3.

Zinc finger protein 521 (ZNF521) participates in the self-renewal of hematopoietic stem cells, and its abnormal expression has been implicated to promote leukemia. However, the specific role of ZNF521 in leukemia has not been fully understood. In this study, we aimed to further elucidate its role. Using acute leukemia cell line THP-1, we demonstrated that knocking down ZNF521 inhibited leukemia cell proliferation, promoted apoptosis, and induced cell arrest in G2/M phase. Interestingly, we also observed the upregulation of SMC3 expression and acetylation, as well as the downregulation of histone deacetylases 8 (HDAC8), CDK2, and CDK6. The proliferation inhibition was reversed by knocking down SMC3, suggesting the key role of SMC3 reduction in ZNF521 elevated proliferation. Conversely, ZNF521 overexpression in HL-60 cells resulted in enhanced proliferation and inhibited apoptosis. Furthermore, we discovered that ZNF521 can interact with HDAC8, which deacetylates SMC3, and the interaction promotes proliferation and suppresses apoptosis. Notably, when HDAC8 was knocked down or its activity was inhibited by a HDAC8 inhibitor, the previous observed trend was reversed. Consequently, ZNF521 plays a critical role in acute myeloid leukemogenesis by reducing the expression and acetylation of SMC3. Overall, this study sheds light on the potential for targeted treatment in highly ZNF521 expressed acute myeloid leukemia, providing a valuable clue for precise and effective therapeutic approaches.

Tackling triple negative breast cancer with HDAC inhibitors: 6 is the isoform!

Triple negative breast cancer (TNBC) is a highly aggressive breast cancer subtype characterized by the lack in the expression of estrogen and progesterone receptors, and human epidermal growth factor receptors 2. TNBC stands out among other breast cancers subtypes for its high aggressiveness and invasiveness, and for the limited therapeutic options available, which justify the poor survival rates registered for this breast cancer subtype. Compelling new evidence pointed out the role of epigenetic modifications in cancer, prompting tumor cell uncontrolled proliferation, epithelial-to-mesenchymal transition, and metastatic events. In this review we showcase the latest evidence supporting the involvement of histone deacetylase 6 (HDAC6) in cancer pathways strictly related to TNBC subtype, also tracking the latest advancements in the identification of novel HDAC6 inhibitors which showed efficacy in TNBC models, offering insights into the potential of targeting this key epigenetic player as an innovative therapeutic option for the treatment of TNBC.

Design, synthesis, and evaluation of a novel TRAIL-activated HDAC6 inhibitor for the treatment of pulmonary fibrosis.

Pulmonary fibrosis (PF) is a common, severe, chronic, and progressive pulmonary interstitial disease characterized by rapid disease progression and high mortality. Despite the Food and Drug Administration (FDA)'s approval of two antifibrotic drugs, nintedanib and pirfenidone, effectively halting the progression of pulmonary fibrosis remains challenging. Histone deacetylase (HDAC) inhibitors have indeed emerged as an important class of antitumour drugs. However, their application in the treatment of fibrotic diseases is still relatively limited. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) has the potential to inhibit fibrotic processes by inducing fibroblast apoptosis. In this study, we designed and synthesized a series of histone deacetylase 6 (HDAC6) inhibitors that activate TRAIL, among which compound 7e exhibited potent inhibitory activity against HDAC6, with an IC50 of 42.90 ± 4.96 nM and superior antiproliferative effects on fibroblasts. Therefore, we further investigated its anti-pulmonary fibrosis effect in mouse models of both idiopathic pulmonary fibrosis (IPF) and silicosis. Our results suggest that compound 7e is a promising candidate for the treatment of pulmonary fibrosis.

Fusobacterium nucleatum facilitates anti-PD-1 therapy in microsatellite stable colorectal cancer.

Microsatellite stable (MSS) colorectal cancers (CRCs) are often resistant to anti-programmed death-1 (PD-1) therapy. Here, we show that a CRC pathogen, Fusobacterium nucleatum (Fn), paradoxically sensitizes MSS CRC to anti-PD-1. Fecal microbiota transplantation (FMT) from patients with Fn-high MSS CRC to germ-free mice bearing MSS CRC confers sensitivity to anti-PD-1 compared to FMT from Fn-low counterparts. Single Fn administration also potentiates anti-PD-1 efficacy in murine allografts and CD34+-humanized mice bearing MSS CRC. Mechanistically, we demonstrate that intratumoral Fn generates abundant butyric acid, which inhibits histone deacetylase (HDAC) 3/8 in CD8+ T cells, inducing Tbx21 promoter H3K27 acetylation and expression. TBX21 transcriptionally represses PD-1, alleviating CD8+ T cell exhaustion and promoting effector function. Supporting this notion, knockout of a butyric acid-producing gene in Fn abolishes its anti-PD-1 boosting effect. In patients with MSS CRC, high intratumoral Fn predicts favorable response to anti-PD-1 therapy, indicating Fn as a potential biomarker of immunotherapy response in MSS CRC.

Sphk1 regulates HMGB1 via HDAC4 and mediates epithelial pyroptosis in allergic rhinitis.

Background: Allergic rhinitis (AR) is a global health issue affecting millions of individuals worldwide. Pyroptosis has emerged as a major player in the development of AR, and targeting its inhibition with specific drugs holds promise for AR treatment. However, a comprehensive understanding of the precise mechanisms underlying pyroptosis in AR remains to be explored, warranting further investigation. Objective: This study aims to elucidate the roles of HMGB1, Sphk1, and HDAC4 in regulating human nasal epithelial cell (hNEC) pyroptosis and AR. Methods: An in vitro AR cell culture model and an in vivo AR mouse model were established. Western blot, ELISA, histological staining, and flow cytometry were utilized to confirm the gene and protein expression. The interactions among Sphk1, HDAC4, and HMGB1 were validated through ChIP, Co-IP, and Dual-luciferase assay. Results and conclusion: We identified that the expression levels of Sphk1, HMGB1, and inflammasome components, including IL-18, and IL-1ß were elevated in AR patients and mouse models. Knockdown of Sphk1 inhibited hNEC pyroptosis induced by dust mite allergen. Overexpression of HDAC4 suppressed HMGB1-mediated pyroptosis in hNECs. In addition, HDAC4 was found to mediate the transcriptional regulation of HMGB1 via MEF2C, a transcription factor. Additionally, Sphk1 was shown to interact with CaMKII-δ, promoting the phosphorylation of HDAC4 and inhibiting its cytoplasmic translocation. Knockdown of HDAC4 reversed the effect of Sphk1 knockdown on pyroptosis. These discoveries offer a glimpse into the molecular mechanisms underlying AR and suggest potential therapeutic targets for the treatment of this condition.

Inhibition of HDAC8 mitigates AKI by reducing DNA damage and promoting homologous recombination repair.

Nephrotoxicity is a major side effect of platinum-based antineoplastic drugs, and there is currently no available therapeutic intervention. Our study suggests that targeting histone deacetylase 8 could be a potential treatment for cisplatin-induced acute kidney injury (AKI). In a murine model of AKI induced by cisplatin, the administration of PCI-34051, a selective inhibitor of HDAC8, resulted in significant improvement in renal function and reduction in renal tubular damage and apoptosis. Pharmacological inhibition of HDAC8 also decreased caspase-3 and PARP1 cleavage, attenuated Bax expression and preserved Bcl-2 levels in the injured kidney. In cultured murine renal epithelial cells (mRTECs) exposed to cisplatin, treatment with PCI-34051 or transfection with HDAC8 siRNA reduced apoptotic cell numbers and diminished expression of cleaved caspase-3 and PARP1; conversely, overexpression of HDAC8 intensified these changes. Additionally, PCI-34051 reduced p53 expression levels along with those for p21, p-CDK2 and γ-H2AX while preserving MRE11 expression in the injured kidney. Similarly, pharmacological and genetic inhibition of HDAC8 reduced γ-H2AX and enhanced MRE11 expression; conversely, HDAC8 overexpression exacerbated these changes in mRTECs exposed to cisplatin. These results support that HDAC8 inhibition attenuates cisplatin-induced AKI through a mechanism associated with reducing DNA damage and promoting its repair.

Isoliquiritigenin ameliorates abnormal oligodendrocyte development and behavior disorders induced by white matter injury.

Background: White matter injury is a predominant form of brain injury in preterm infants. However, effective drugs for its treatment are currently lacking. Previous studies have shown the neuroprotective effects of Isoliquiritigenin (ISL), but its impact on white matter injury in preterm infants remains poorly understood. Aims: This study aimed to investigate the protective effects of ISL against white matter injury caused by infection in preterm infants using a mouse model of lipopolysaccharide-induced white matter injury, integrating network pharmacology as well as in vivo and in vitro experiments. Methods: This study explores the potential mechanisms of ISL on white matter injury by integrating network pharmacology. Core pathways and biological processes affected by ISL were verified through experiments, and motor coordination, anxiety-like, and depression-like behaviors of mice were evaluated using behavioral experiments. White matter injury was observed using hematoxylin-eosin staining, Luxol Fast Blue staining, and electron microscopy. The development of oligodendrocytes and the activation of microglia in mice were assessed by immunofluorescence. The expression of related proteins was detected by Western blot. Results: We constructed a drug-target network, including 336 targets associated with ISL treatment of white matter injury. The biological process of ISL treatment of white matter injury mainly involves microglial inflammation regulation and myelination. Our findings revealed that ISL reduced early nerve reflex barriers and white matter manifestations in mice, leading to decreased activation of microglia and release of proinflammatory cytokines. Additionally, ISL demonstrated the ability to mitigate impairment in oligodendrocyte development and myelination, ultimately improving behavior disorders in adult mice. Mechanistically, we observed that ISL downregulated HDAC3 expression, promoted histone acetylation, enhanced the expression of H3K27ac, and regulated oligodendrocyte pro-differentiation factors. Conclusion: These findings suggest that ISL can have beneficial effects on white matter injury in preterm infants by alleviating inflammation and promoting oligodendrocyte differentiation.

NEDD9 is transcriptionally regulated by HDAC4 and promotes breast cancer metastasis and macrophage M2 polarization via the FAK/NF-κB signaling pathway.

BACKGROUND: Breast cancer is a malignancy with a generally poor prognosis. With the advancement of molecular research, we have gained deeper insights into the cellular processes that drive breast cancer development. However, the precise mechanisms remain elusive. RESULTS: Based on the CPTAC database, we found that NEDD9 expression is up-regulated in breast cancer tissues and is associated with poor prognosis in breast cancer patients. Functional experiments showed that NEDD9 promotes tumor growth and metastasis both in vitro and in vivo. Overexpression of NEDD9 disrupts mammary epithelial acinus formation and triggers epithelial-mesenchymal transition in breast cancer cells, effects that are reversed upon NEDD9 gene silencing. Mechanistically, NEDD9 upregulates its expression by inhibiting HDAC4 activity, leading to enhanced H3K9 acetylation of the NEDD9 gene promoter and activation of the FAK/NF-κB signaling pathway. Furthermore, NEDD9 overexpression promotes IL-6 secretion, which further drives breast cancer progression. Notably, NEDD9 activation fosters the pro-tumoral M2 macrophage polarization in the tumor microenvironment. NEDD9 stimulates IL-6 secretion, polarizes monocytes towards an M2-like phenotype, and enhances BC cell invasiveness. CONCLUSIONS: These findings suggest that NEDD9 upregulation plays a pivotal role in breast cancer metastasis and macrophage M2 polarization via the FAK/NF-κB signaling axis. Targeting NEDD9 may offer a promising therapeutic approach for breast cancer treatment.

Melatonin Attenuates Diabetic Retinopathy by Regulating EndMT of Retinal Vascular Endothelial Cells via Inhibiting the HDAC7/FOXO1/ZEB1 Axis.

Diabetic retinopathy (DR) is characterized as a microvascular disease. Nonproliferative diabetic retinopathy (NPDR) presents with alterations in retinal blood flow and vascular permeability, thickening of the basement membrane, loss of pericytes, and formation of acellular capillaries. Endothelial-mesenchymal transition (EndMT) of retinal microvessels may play a critical role in advancing NPDR. Melatonin, a hormone primarily secreted by the pineal gland, is a promising therapeutic for DR. This study explored the EndMT in retinal microvessels of NPDR and its related mechanisms. The effect of melatonin on the retina of diabetic rats was evaluated by electroretinogram (ERG) and histopathologic slide staining. Furthermore, the effect of melatonin on human retinal microvascular endothelial cells (HRMECs) was detected by EdU incorporation assay, scratch assay, transwell assay, and tube formation test. Techniques such as RNA-sequencing, overexpression or knockdown of target genes, extraction of cytoplasmic and nuclear protein, co-immunoprecipitation (co-IP), and multiplex immunofluorescence facilitated the exploration of the mechanisms involved. Our findings reveal, for the first time, that melatonin attenuates diabetic retinopathy by regulating EndMT of retinal vascular endothelial cells via inhibiting the HDAC7/FOXO1/ZEB1 axis. Collectively, these results suggest that melatonin holds potential as a therapeutic strategy to reduce retinal vascular damage and protect vision in NPDR.

Astragaloside I from Astragalus Attenuates Diabetic Kidney Disease by Regulating HDAC3/Klotho/TGF-ß1 Loop.

Diabetic kidney disease (DKD) has become the primary cause of end-stage renal disease (ESRD), causing an urgent need for preventive strategies for DKD. Astragaloside I (ASI), a bioactive saponin extracted from Astragalus membranaceus (Fisch.) Bunge has been demonstrated to possess a variety of biological activities. This study investigates the therapeutic potential of ASI in DKD and the underlying molecular mechanism using db/db mice in vivo and high glucose (HG)-induced SV40-MES-13 cells in vitro. The results indicated that ASI significantly ameliorated renal dysfunction and mitigated the pathological alterations in the renal tissues of db/db mice. Moreover, ASI was found to reduce the levels of renal fibrosis makers and suppress the activation of TGF-[Formula: see text]1/Smad2/3 pathway in both db/db mice and HG-induced SV40-MES-13 cells. Furthermore, ASI downregulated HDAC3 expression, upregulated Klotho expression, and enhanced Klotho release. ASI is directly bound to HDAC3, and the beneficial effects of ASI on Klotho/TGF-[Formula: see text]1/Smad2/3-mediciated renal fibrosis in DKD were reversed by the HDAC3 agonist ITSA-1. In conclusion, ASI attenuates renal fibrosis in DKD, and may act through concurrently inhibiting HDAC3 and TGF-[Formula: see text]1, thereby regulating HDAC3-mediciated Klotho/TGF-[Formula: see text]1/Smad2/3 pathway.

Impact of HDAC inhibitors on macrophage polarization to enhance innate immunity against infections.

Innate immunity plays an important role in host defense against pathogenic infections. It involves macrophage polarization into either the pro-inflammatory M1 or the anti-inflammatory M2 phenotype, influencing immune stimulation or suppression, respectively. Epigenetic changes during immune reactions contribute to long-term innate immunity imprinting on macrophage polarization. It is becoming increasingly evident that epigenetic modulators, such as histone deacetylase (HDAC) inhibitors (HDACi), enable the enhancement of innate immunity by tailoring macrophage polarization in response to immune stressors. In this review, we summarize current literature on the impact of HDACi and other epigenetic modulators on the functioning of macrophages during diseases that have a strong immune component, such as infections. Depending on the disease context and the chosen therapeutic intervention, HDAC1, HDAC2, HDAC3, HDAC6, or HDAC8 are particularly important in influencing macrophage polarization towards either M1 or M2 phenotypes. We anticipate that therapeutic strategies based on HDAC epigenetic mechanisms will provide a unique approach to boost immunity against disease challenges, including resistant infections.

Impact of HDAC6-mediated progesterone receptor expression on the response of breast cancer cells to hormonal therapy.

Modulation of estrogen receptor (ER) and progesterone receptor (PR) expression, as well as their emerging functional crosstalk, remains a potential approach for enhancing the response to hormonal therapy in breast cancer. Aberrant epigenetic alterations induced by histone deacetylases (HDACs) were massively implicated in dysregulating the function of hormone receptors in breast cancer. Although much is known about the regulation of ER signaling by HDAC, the precise role of HDAC in modulating the expression of PR and its impact on the outcomes of hormonal therapy is poorly defined. Here, we demonstrate the involvement of HDAC6 in regulating PR expression in breast cancer cells. The correlation between HDAC6 and hormone receptors was investigated in patients' tissues by immunohistochemistry (n = 80) and publicly available data (n = 3260) from breast cancer patients. We explored the effect of modulating the expression of HDAC6 as well as its catalytic inhibition on the level of hormone receptors by a variety of molecular analyses, including Western blot, immunofluorescence, Real-time PCR, RNA-seq analysis and chromatin immunoprecipitation. Based on our in-silico and immunohistochemistry analyses, HDAC6 levels were negatively correlated with PR status in breast cancer tissues. The downregulation of HDAC6 enhanced the expression of PR-B in hormone receptor-positive and triple-negative breast cancer (TNBC) cells. The selective targeting of HDAC6 by tubacin resulted in the enrichment of the H3K9 acetylation mark at the PGR-B gene promoter region and enhanced the expression of PR-B. Additionally, transcriptomic analysis of tubacin-treated cells revealed enhanced activity of acetyltransferase and growth factor signaling pathways, along with the enrichment of transcription factors involved in the transcriptional activity of ER, underscoring the crucial role of HDAC6 in regulating hormone receptors. Notably, the addition of HDAC6 inhibitor potentiated the effects of anti-ER and anti-PR drugs mainly in TNBC cells. Together, these data highlight the role of HDAC6 in regulating PR expression and provide a promising therapeutic approach for boosting breast cancer sensitivity to hormonal therapy.

Microtubule dynamics in cancer metastasis: Harnessing the underappreciated potential for therapeutic interventions.

Microtubules, dynamic cytoskeletal structures crucial for cellular processes, have surfaced as promising targets for cancer therapy owing to their pivotal role in cancer progression and metastasis. This review comprehensively explores the multifaceted landscape of microtubule-targeting drugs and their potential to inihibit cancer metastasis. Although the role of Actin cytoskeleton is well known in controlling metastasis, only recently Microtubules are emerging as a potential controller of metastasis. We delve into the processes at the core of antimetastatic impacts of microtubule-targeting agents, both through direct modulation of microtubules and via alternative pathways. Drawing from in vitro and in vivo studies, we analyze the cytotoxic and antimetastatic doses of various compounds, shedding light on their therapeutic potential. Furthermore, we discuss the emerging class of microtubule targeting drugs, and their role in metastasis inhibition, such as microtubules acetylation inhibitory drugs, particularly histone deacetylase inihibitors and antibody-drug conjugates. Histone deacetylase (HDAC) strengthens the microtubule cytoskeleton through acetylation. Recently, HDAC inhibitors have been discovered to have antimetastatic properties. Here, the role of HDAC inhibitors in stopping metastasis is discussed with respect to microtubule cytoskeleton. Surprisingly, novel antibody conjugates of microtubule-targeting agents, which are in clinical trials, were found to be antimetastatic. This review discusses these antibody conjugates in detail. Additionally, we elucidate the intricate crosstalk between microtubules and other cytoskeletal proteins, unveiling novel therapeutic strategies for metastasis suppression. By providing a wide-ranging overview of the complex interplay between microtubules and cancer metastasis, this review contributes to the comprehension of cancer's biological mechanisms and the development of innovative therapeutic interventions to mitigate metastatic progression.

miRNA-105-5p regulates the histone deacetylase HDAC2 through FOXG1 to affect the malignant biological behavior of triple-negative breast cancer cells.

BACKGROUND: Triple-negative breast cancer (TNBC) is a specific subtype of breast cancer (BC). Some potential molecular targets have been identified, and miR-105-5p was found to be abnormally expressed in TNBC tissues. OBJECTIVE: The objective of this study was to probe the effect of miR-105-5p on TNBC via FOXG1/HDAC2-mediated acetylation. METHODS: An animal model of TNBC was established by injecting BC cells into the axillary area of nude mice. The levels of miR-105-5p, FOXG1, HDAC2, Bcl-2, Bax, and Ki67 were detected via RT‒qPCR, Western blotting and immunohistochemistry. Flow cytometry, CCK-8, Transwell and colony formation assays were used to measure apoptosis, proliferation and migration, respectively. Total histone acetylation levels were measured by ELISA. The binding of FOXG1 to HDAC2 was detected by co-immunoprecipitation. The binding relationship between miR-105-5p and FOXG1 was verified using a dual-luciferase reporter gene assay. RESULTS: In this study, miR-105-5p and HDAC2 were highly expressed in the MDA-MB-231 and BT-549 BC cell lines, whereas FOXG1 was expressed at low levels. The inhibition of miR-105-5p inhibited the proliferation and migration of MDA-MB-231 and BT-549 cells and promoted their apoptosis. Bioinformatics analysis revealed that miR-105-5p and FOXG1 had a negative targeting regulatory relationship. FOXG1 overexpression had a similar effect on cancer cells as the inhibition of miR-105-5p. Moreover, experiments revealed that FOXG1 and HDAC2 could bind to each other and that HDAC2 overexpression or treatment with the histone acetyltransferase inhibitor Garcinol weakened the effect of FOXG1 overexpression. In addition, FOXG1 knockdown inhibited the effect of the miR-105-5p inhibitor, while Garcinol treatment further enhanced the effect of FOXG1 knockdown, inhibited histone acetylation, promoted the proliferation and migration of cancer cells, and inhibited apoptosis. Moreover, the in vivo results confirmed the in vitro results. CONCLUSION: miR-105-5p promotes HDAC2 expression by reducing FOXG1, inhibits histone acetylation, and aggravates the malignant biological behavior of TNBC cells.

Synergistic Cytotoxicity of Histone Deacetylase and Poly-ADP Ribose Polymerase Inhibitors and Decitabine in Breast and Ovarian Cancer Cells: Implications for Novel Therapeutic Combinations.

Breast and ovarian cancers pose significant therapeutic challenges. We explored the synergistic cytotoxicity of histone deacetylase inhibitors (HDACis), poly(ADP-ribose) polymerase inhibitors (PARPis), and decitabine in breast (MDA-MB-231 and MCF-7) and ovarian (HEY-T30 and SKOV-3) cancer cell lines that were exposed to HDACi (panobinostat or vorinostat), PARPi (talazoparib or olaparib), decitabine, or their combinations. HDACi, PARPi, and decitabine combinations had synergistic cytotoxicity (assessed by MTT and clonogenic assays) in all cell lines (combination index < 1). Clonogenic assays confirmed the sensitivity of breast and ovarian cancer cell lines to the three-drug combinations (panobinostat, talazoparib, and decitabine; panobinostat, olaparib, and decitabine; vorinostat, talazoparib, and decitabine; vorinostat, olaparib, and decitabine). Cell proliferation was inhibited by 48-70%, and Annexin V positivity was 42-59% in all cell lines exposed to the three-drug combinations. Western blot analysis showed protein PARylation inhibition, caspase 3 and PARP1 cleavage, and c-MYC down-regulation. The three-drug combinations induced more DNA damage (increased phosphorylation of histone 2AX) than the individual drugs, impaired the DNA repair pathways, and altered the epigenetic regulation of gene expression. These results indicate that HDACi, PARPi, and decitabine combinations should be further explored in these tumor types. Further clinical validation is warranted to assess their safety and efficacy.

Advances in understanding the roles of plant HAT and HDAC in non-histone protein acetylation and deacetylation.

MAIN CONCLUSION: This review focuses on HATs and HDACs that modify non-histone proteins, summarizes functional mechanisms of non-histone acetylation as well as the roles of HATs and HDACs in rice and Arabidopsis. The growth and development of plants, as well as their responses to biotic and abiotic stresses, are governed by intricate gene and protein regulatory networks, in which epigenetic modifying enzymes play a crucial role. Histone lysine acetylation levels, modulated by histone acetyltransferases (HATs) and histone deacetylases (HDACs), are well-studied in the realm of transcriptional regulation. However, the advent of advanced proteomics has unveiled that non-histone proteins also undergo acetylation, with its underlying mechanisms now being clarified. Indeed, non-histone acetylation influences protein functionality through diverse pathways, such as modulating protein stability, adjusting enzymatic activity, steering subcellular localization, influencing interactions with other post-translational modifications, and managing protein-protein and protein-DNA interactions. This review delves into the recent insights into the functional mechanisms of non-histone acetylation in plants. We also provide a summary of the roles of HATs and HDACs in rice and Arabidopsis, and explore their potential involvement in the regulation of non-histone proteins.

Therapeutic indications for HDAC6 inhibitors in the peripheral and central nervous disorders.

INTRODUCTION: Inhibition of the enzymatic function of HDAC6 is currently being explored in clinical trials ranging from peripheral neuropathies to cancers. Advances in selective HDAC6 inhibitor discovery allowed studying highly efficacious brain penetrant and peripheral restrictive compounds for treating PNS and CNS indications. AREAS COVERED: This review explores the multifactorial role of HDAC6 in cells, the common pathological hallmarks of PNS and CNS disorders, and how HDAC6 modulates these mechanisms. Pharmacological inhibition of HDAC6 and genetic knockout/knockdown studies as a therapeutic strategy in PNS and CNS indications were analyzed. Furthermore, we describe the recent developments in HDAC6 PET tracers and their utility in CNS indications. Finally, we explore the advancements and challenges with HDAC6 inhibitor compounds, such as hydroxamic acid, fluoromethyl oxadiazoles, HDAC6 degraders, and thiol-based inhibitors. EXPERT OPINION: Based on extensive preclinical evidence, pharmacological inhibition of HDAC6 is a promising approach for treating both PNS and CNS disorders, given its involvement in neurodegeneration and aging-related cellular processes. Despite the progress in the development of selective HDAC6 inhibitors, safety concerns remain regarding their chronic administration in PNS and CNS indications, and the development of novel compound classes and modalities inhibiting HDAC6 function offer a way to mitigate some of these safety concerns.

Butyrate and propionate are microbial danger signals that activate the NLRP3 inflammasome in human macrophages upon TLR stimulation.

Short-chain fatty acids (SCFAs) are immunomodulatory compounds produced by the microbiome through dietary fiber fermentation. Although generally considered beneficial for gut health, patients suffering from inflammatory bowel disease (IBD) display poor tolerance to fiber-rich diets, suggesting that SCFAs may have contrary effects under inflammatory conditions. To investigate this, we examined the effect of SCFAs on human macrophages in the presence of Toll-like receptor (TLR) agonists. In contrast to anti-inflammatory effects under steady-state conditions, we found that butyrate and propionate activated the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome in the presence of TLR agonists. Mechanistically, these SCFAs prevented transcription of FLICE-like inhibitory protein (cFLIP) and interleukin-10 (IL-10) through histone deacetylase (HDAC) inhibition, triggering caspase-8-dependent NLRP3 inflammasome activation. SCFA-driven NLRP3 activation was potassium efflux independent and did not result in cell death but rather triggered hyperactivation and IL-1ß release. Our findings demonstrate that butyrate and propionate are bacterially derived danger signals that regulate NLRP3 inflammasome activation through epigenetic modulation of the inflammatory response.