Histone Deacetylase Inhibitor Research Articles

Epigenetic mechanisms differentially regulate blood pressure and renal dysfunction in male and female Npr1 haplotype mice.

We determined the epigenetic mechanisms regulating mean arterial pressure (MAP) and renal dysfunction in guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) gene-targeted mice. The Npr1 (encoding NPRA) gene-targeted mice were treated with class 1 specific histone deacetylase inhibitor (HDACi) mocetinostat (MGCD) to determine the epigenetic changes in a sex-specific manner. Adult male and female Npr1 haplotype (1-copy; Npr1+/-), wild-type (2-copy; Npr1+/+), and gene-duplicated heterozygous (3-copy; Npr1++/+) mice were intraperitoneally injected with MGCD (2 mg/kg) for 14 days. BP, renal function, histopathology, and epigenetic changes were measured. One-copy male mice showed significantly increased MAP, renal dysfunction, and fibrosis than 2-copy and 3-copy mice. Furthermore, HDAC1/2, collagen1alpha-2 (Col1α-2), and alpha smooth muscle actin (α-SMA) were significantly increased in 1-copy mice compared with 2-copy controls. The expression of antifibrotic microRNA-133a was attenuated in 1-copy mice but to a greater extent in males than females. NF-κB was localized at significantly lower levels in cytoplasm than in the nucleus with stronger DNA binding activity in 1-copy mice. MGCD significantly lowered BP, improved creatinine clearance, and repaired renal histopathology. The inhibition of class I HDACs led to a sex-dependent distinctive stimulation of acetylated positive histone marks and inhibition of methylated repressive histone marks in Npr1 1-copy mice; however, it epigenetically lowered MAP, repaired renal fibrosis, and proteinuria and suppressed NF-kB differentially in males versus females. Our results suggest a role for epigenetic targets affecting hypertension and renal dysfunction in a sex-specific manner.

Multi-omics and pharmacological characterization of patient-derived glioma cell lines

Glioblastoma (GBM) is the most common brain tumor and remains incurable. Primary GBM cultures are widely used tools for drug screening, but there is a lack of genomic and pharmacological characterization for these primary GBM cultures. Here, we collect 50 patient-derived glioma cell (PDGC) lines and characterize them by whole genome sequencing, RNA sequencing, and drug response screening. We identify three molecular subtypes among PDGCs: mesenchymal (MES), proneural (PN), and oxidative phosphorylation (OXPHOS). Drug response profiling reveals that PN subtype PDGCs are sensitive to tyrosine kinase inhibitors, whereas OXPHOS subtype PDGCs are sensitive to histone deacetylase inhibitors, oxidative phosphorylation inhibitors, and HMG-CoA reductase inhibitors. PN and OXPHOS subtype PDGCs stably form tumors in vivo upon intracranial transplantation into immunodeficient mice, whereas most MES subtype PDGCs fail to form tumors in vivo. In addition, PDGCs cultured by serum-free medium, especially long-passage PDGCs, carry MYC/MYCN amplification, which is rare in GBM patients. Our study provides a valuable resource for understanding primary glioma cell cultures and clinical translation and highlights the problems of serum-free PDGC culture systems that cannot be ignored.

Effects of Dietary Fiber, Phenolic Compounds, and Fatty Acids on Mental Health: Possible Interactions with Genetic and Epigenetic Aspects

Scientific evidence shows that dietary patterns are a key environmental determinant of mental health. Dietary constituents can modify epigenetic patterns and thus the gene expression of relevant genetic variants in various mental health conditions. In the present work, we describe some nutrigenomic effects of dietary fiber, phenolic compounds (plant secondary metabolites), and fatty acids on mental health outcomes, with emphasis on their possible interactions with genetic and epigenetic aspects. Prebiotics, through their effects on the gut microbiota, have been associated with modulation in the neuroendocrine response to stress and the facilitation of the processing of positive emotions. Some of the genetic and epigenetic mechanisms include the serotonin neurotransmitter system (TPH1 gene) and the brain-derived neurotrophic factor (inhibition of histone deacetylases). The consumption of phenolic compounds exerts a positive role in neurocognitive domains. The evidence showing the involvement of genetic and epigenetic factors comes mainly from animal models, highlighting the role of epigenetic mechanisms through miRNAs and methyltransferases as well as the effect on the expression of apoptotic-related genes. Long-chain n-3 fatty acids (EPA and DHA) have been mainly related to psychotic and mood disorders, but the genetic and epigenetic evidence is scarce. Studies on the genetic and epigenetic basis of these interactions need to be promoted to move towards a precision and personalized approach to medicine.

HDAC3 genetic and pharmacologic inhibition radiosensitizes fusion positive rhabdomyosarcoma by promoting DNA double-strand breaks

Radiotherapy (RT) plays a critical role in the management of rhabdomyosarcoma (RMS), the prevalent soft tissue sarcoma in childhood. The high risk PAX3-FOXO1 fusion-positive subtype (FP-RMS) is often resistant to RT. We have recently demonstrated that inhibition of class-I histone deacetylases (HDACs) radiosensitizes FP-RMS both in vitro and in vivo. However, HDAC inhibitors exhibited limited success on solid tumors in human clinical trials, at least in part due to the presence of off-target effects. Hence, identifying specific HDAC isoforms that can be targeted to radiosensitize FP-RMS is imperative. We, here, found that only HDAC3 silencing, among all class-I HDACs screened by siRNA, radiosensitizes FP-RMS cells by inhibiting colony formation. Thus, we dissected the effects of HDAC3 depletion using CRISPR/Cas9-dependent HDAC3 knock-out (KO) in FP-RMS cells, which resulted in Endoplasmatic Reticulum Stress activation, ERK inactivation, PARP1- and caspase-dependent apoptosis and reduced stemness when combined with irradiation compared to single treatments. HDAC3 loss-of-function increased DNA damage in irradiated cells augmenting H2AX phosphorylation and DNA double-strand breaks (DSBs) and counteracting irradiation-dependent activation of ATM and DNA-Pkcs as well as Rad51 protein induction. Moreover, HDAC3 depletion hampers FP-RMS tumor growth in vivo and maximally inhibits the growth of irradiated tumors compared to single approaches. We, then, developed a new HDAC3 inhibitor, MC4448, which showed specific cell anti-tumor effects and mirrors the radiosensitizing effects of HDAC3 depletion in vitro synergizing with ERKs inhibition. Overall, our findings dissect the pro-survival role of HDAC3 in FP-RMS and suggest HDAC3 genetic or pharmacologic inhibition as a new promising strategy to overcome radioresistance in this tumor.

Histone deacetylases facilitate Th17-cell differentiation and pathogenicity in autoimmune uveitis via CDK6/ID2 axis

IntroductionAutoimmune uveitis (AU) is a prevalent ocular autoimmune disease leading to significant visual impairment. However, underlying pathogenesis of AU required to develop more efficient therapy remain unclear. MethodsWe isolated peripheral blood mononuclear cells (PBMCs) from AU patients and performed single-cell RNA sequencing (scRNA-seq). Besides, experimental autoimmune uveitis (EAU) model was established and treated with histone deacetylase inhibitor (HDACi) Belinostat or vehicle. We extracted immune cells from Blank, EAU, and HDACi-treated EAU mice and used scRNA-seq, flow cytometry, siRNA, specific inhibitors, and adoptive transfer experiments to explore the role of HDACs and its downstream potential molecular mechanisms in the immune response of EAU and AU. ResultsWe found highly expressed histone deacetylases (HDACs) family in AU patients and identified it as a key factor related to CD4+ effector T cell differentiation in the pathogenesis of AU. Our further studies showed that targeted inhibition of HDACs effectively alleviated EAU, restored its Th17/Treg balance, and reduced inflammatory gene expression, especially in CD4+ T cells. Post-HDACs inhibition, Treg proportions increased with enhanced immunomodulatory effects. Importantly, HDACs exhibited a positive promoting role on Th17 cells. Based on scRNA-seq screening and application of knock-down siRNAs and specific inhibitors in vitro and vivo, we identified CDK6 as a key downstream molecule regulated by HDAC1/3/6 through acetyl-histone H3/p53/p21 axis, which is involved in Th17 pathogenicity and EAU development. Additionally, HDACs-regulated CDK6 formed a positive loop with ID2, inducing PIM1 upregulation, promoting Th17 cell differentiation and pathogenicity, and correlates with AU progression. ConclusionBased on the screening of clinical samples and downstream molecular functional validation experiments, we revealed a driving role for HDACs and the HDACs-regulated CDK6/ID2 axis in Th17 cell differentiation and pathogenicity in AU, proposing a promising therapeutic strategy.

Anti-tumour activity of Panobinostat in oesophageal adenocarcinoma and squamous cell carcinoma cell lines

BackgroundOesophageal cancer remains a challenging disease with high mortality rates and few therapeutic options. In view of these difficulties, epigenetic drugs have emerged as potential alternatives for patient care. The goal of this study was to evaluate the effect and biological consequences of Panobinostat treatment, an HDAC (histone deacetylase) inhibitor already approved for treatment of patients with multiple myeloma, in oesophageal cell lines of normal and malignant origin, with the latter being representative of the two main histological subtypes: adenocarcinoma and squamous cell carcinoma.ResultsPanobinostat treatment inhibited growth and hindered proliferation, colony formation and invasion of oesophageal cancer cells. Considering HDAC tissue expression, HDAC1 was significantly upregulated in normal oesophageal epithelium in comparison with tumour tissue, whereas HDAC3 was overexpressed in oesophageal cancer compared to non-malignant mucosa. No differences between normal and tumour tissue were observed for HDAC2 and HDAC8 expression.ConclusionsPanobinostat exposure effectively impaired malignant features of oesophageal cancer cells. Because HDAC3 was shown to be overexpressed in oesophageal tumour samples, this epigenetic drug may represent an alternative therapeutic option for oesophageal cancer patients.

Hydrazides as Inhibitors of Histone Deacetylases.

In this Perspective, we have brought together available biological evidence on hydrazides as histone deacetylase inhibitors (HDACis) and as a distinct type of Zn-binding group (ZBG) to be reviewed for the first time in the literature. N-Alkyl hydrazides have transformed the field, providing innovative and practical chemical tools for selective and effective inhibition of specific histone deacetylase (HDAC) enzymes, in addition to the usual hydroxamic acid and o-aminoanilide ZBG-bearing HDACis. This has enabled efficient targeting of neurodegenerative diseases such as Alzheimer's disease, cancer, cardiovascular diseases, and protozoal pathologies.

Dual targeting of histone deacetylases and MYC as potential treatment strategy for H3-K27M pediatric gliomas.

Diffuse midline gliomas (DMGs) are aggressive and fatal pediatric tumors of the central nervous system that are highly resistant to treatments. Lysine to methionine substitution of residue 27 on histone H3 (H3-K27M) is a driver mutation in DMGs, reshaping the epigenetic landscape of these cells to promote tumorigenesis. H3-K27M gliomas are characterized by deregulation of histone acetylation and methylation pathways, as well as the oncogenic MYC pathway. In search of effective treatment, we examined the therapeutic potential of dual targeting of histone deacetylases (HDACs) and MYC in these tumors. Treatment of H3-K27M patient-derived cells with Sulfopin, an inhibitor shown to block MYC-driven tumors in vivo, in combination with the HDAC inhibitor Vorinostat, resulted in substantial decrease in cell viability. Moreover, transcriptome and epigenome profiling revealed synergistic effect of this drug combination in downregulation of prominent oncogenic pathways such as mTOR. Finally, in vivo studies of patient-derived orthotopic xenograft models showed significant tumor growth reduction in mice treated with the drug combination. These results highlight the combined treatment with PIN1 and HDAC inhibitors as a promising therapeutic approach for these aggressive tumors.

Dual targeting of histone deacetylases and MYC as potential treatment strategy for H3-K27M pediatric gliomas

Diffuse midline gliomas (DMGs) are aggressive and fatal pediatric tumors of the central nervous system that are highly resistant to treatments. Lysine to methionine substitution of residue 27 on histone H3 (H3-K27M) is a driver mutation in DMGs, reshaping the epigenetic landscape of these cells to promote tumorigenesis. H3-K27M gliomas are characterized by deregulation of histone acetylation and methylation pathways, as well as the oncogenic MYC pathway. In search of effective treatment, we examined the therapeutic potential of dual targeting of histone deacetylases (HDACs) and MYC in these tumors. Treatment of H3-K27M patient-derived cells with Sulfopin, an inhibitor shown to block MYC-driven tumors in vivo, in combination with the HDAC inhibitor Vorinostat, resulted in substantial decrease in cell viability. Moreover, transcriptome and epigenome profiling revealed synergistic effect of this drug combination in downregulation of prominent oncogenic pathways such as mTOR. Finally, in vivo studies of patient-derived orthotopic xenograft models showed significant tumor growth reduction in mice treated with the drug combination. These results highlight the combined treatment with PIN1 and HDAC inhibitors as a promising therapeutic approach for these aggressive tumors.

Pharmacological inhibition of histone deacetylase alleviates chronic unpredictable stress induced atherosclerosis and endothelial dysfunction via upregulation of BDNF

Long-term stress is a significant risk factor for cardiovascular diseases, including atherosclerosis and endothelial dysfunction. Moreover, prolonged stress has shown to negatively regulate central BDNF expression. The role of central BDNF in CNS disorders is well studied until recently the peripheral BDNF was also found to be involved in endothelial function regulation and atherosclerosis. The peripheral BDNF and its role in chronic stress-induced atherosclerosis and endothelial dysfunction remain unclear. Therefore, we aimed to elucidate the role of BDNF and its modulation by the HDAC inhibitor valproic acid (VA) in chronic unpredictable stress (CUS)-induced atherosclerosis and endothelial dysfunction. We demonstrated that a 10-week CUS mouse model substantially decreases central and peripheral BDNF expression, resulting in enhanced serum lipid indices, plaque deposition, fibrosis, and CD68 expression in thoracic aortas. Further, parameters associated with endothelial dysfunction such as increased levels of endothelin-1 (ET-1), adhesion molecules like VCAM-1, M1 macrophage markers, and decreased M2 macrophage markers, eNOS expression, and nitrite levels in aortas, were also observed. VA (50 mg/kg, 14 days, i. p.) was administered to mice following 8 weeks of CUS exposure until the end of the experimental procedure. VA significantly prevented the decrease in BDNF, eNOS and nitrite levels, reduced lesion formation and fibrosis in thoracic aortas and increased ET-1, and VCAM-1 followed by M2 polarization in VA-treated mice. The study highlights the potential of epigenetic modulation of BDNF as a therapeutic target, in stress-induced cardiovascular pathologies and suggests that VA could be a promising agent for mitigating CUS-induced endothelial dysfunction and atherosclerosis by BDNF modulation.

Epigenetic agents plus anti-PD-1 reprograms tumor microenvironment and restores antitumor efficacy in Hodgkin lymphoma

DNA methyltransferase inhibitor decitabine plus anti-PD-1 (DP) combination therapy was effective in relapsed/refractory classic Hodgkin lymphoma (cHL). However, a subset of patients experienced primary resistance or relapse/progression after DP therapy. In this study, we evaluated the efficacy and safety of a triplet regimen consisting of the histone deacetylase inhibitor chidamide, decitabine and anti-PD-1 camrelizumab (CDP) in 52 patients with relapsed/refractory cHL who had previously received DP therapy (NCT04233294). CDP treatment was well-tolerate and resulted in an objective response rate of 94% (95% CI, 84-99%), with 50% (95% CI, 36-64%) of patients achieving complete response (CR). Notably, all patients who were recalcitrant to previous DP treatment exhibited therapeutic responses following CDP therapy, although their CR rate was lower compared to patients responsive to prior DP. Overall, the median progression-free survival following CDP therapy was 29.4 months. Through single-cell RNA sequencing of pre-treatment and on-treatment cHL tumor biopsies, we observed the heterogeneity of rare malignant Hodgkin Reed/Sternberg (HRS)-like cells. The classical CD30+ HRS-like cells interacted with the abundant immunosuppressive IL21+CD4+ T helper cells, forming a positive feedback loop that supported their survival. In contrast, the CD30- HRS-like cell population showed potential resistance to anti-PD-1 immunotherapy. CDP treatment promoted the activation of diverse tumor-reactive CD8+ T cells and suppressed the proliferation of IL21+CD4+ T cells by inhibiting STAT1/3 signaling, thereby alleviating their immunosuppressive effects. These findings provide insights into the cHL microenvironment that contributes to anti-PD-1 resistance and highlight the therapeutic effectiveness of dual epi-immunotherapy in overcoming immunotherapy resistance.

ACAP3 negatively regulated by HDAC2 inhibits the malignant development of papillary thyroid carcinoma cells

ArfGAP with coiled-coil, ankyrin repeat and PH domains 3 (ACAP3) level has been confirmed to be downregulated in papillary thyroid carcinoma (PTC). Histone deacetylase inhibitors (HDACIs) have therapeutic effects on PTC. Accordingly, this study probed into the potential relation of HDACIs and ACAP3 in PTC. Expressions of ACAP3 and histone deacetylase 2 (HDAC2) in PTC were investigated by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between HDAC2 and ACAP3 was predicted by Pearson analysis. Cell functional assays (cell counting kit-8, transwell, wound healing and flow cytometry assays) and rescue assay were carried out to determine the effects of HDAC2/ACAP3 axis on biological behaviors of PTC cells. Expressions of apoptosis-, epithelial-mesenchymal transition-, Protein Kinase B (AKT)-, and P53-related proteins were measured by Western blot. ACAP3 level was downregulated in PTC tissues and cells. ACAP3 overexpression (oe-ACAP3) suppressed viability, proliferation, migration and invasion of PTC cells, facilitated apoptosis, downregulated the expressions of Protein Kinase B (Bcl-2) and N-cadherin, upregulated the expressions of Bcl-2 associated protein X (Bax) and E-cadherin, diminished the p-AKT/AKT ratio and elevated the p-p53/p53 ratio; however, ACAP3 silencing or HDAC2 overexpression (oe-HDAC2) did the opposite. HDAC2 negatively correlated with ACAP3. The tumor-suppressing effect of oe-ACAP3 in PTC was reversed by oe-HDAC2. Collectively, ACAP3 negatively regulated by HDAC2 suppresses the proliferation and metastasis while facilitating apoptosis of PTC cells.

BCL6 confers resistance to HDAC inhibitors in DLBCL

Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin lymphoma with limited response to chemotherapy. Histone acetylation is reduced in DLBCL. Chidamide, a histone deacetylase inhibitor, shows promise in lymphomas but needs further investigation for DLBCL. Our study indicated that chidamide effectively suppresses DLBCL both in vitro and in vivo. High-throughput RNA sequencing analysis provided comprehensive evidence that chidamide markedly influences crucial signaling pathways in DLBCL, including the MAPK, MYC and p53 pathway. Additionally, we observed substantial variability in the sensitivity of DLBCL cells to chidamide, and identified that elevated expression of BCL6 might confer resistance to chidamide in DLBCL. Moreover, our investigations revealed that BCL6 inhibited chidamide-induced histone acetylation by recruiting histone deacetylase (HDACs), leading to drug resistance in DLBCL cells. Furthermore, we found that lenalidomide targeted BCL6 degradation through the ubiquitination pathway and restore the sensitivity of drug-resistant DLBCL to chidamide. Collectively, these findings provided valuable insights into the global impact of chidamide on DLBCL and highlight the potential of targeting HDACs as a therapeutic strategy for DLBCL. Identifying BCL6 as a biomarker for predicting the response to chidamide and the combination therapy with BCL6 inhibition has the potential to lead to more personalized and effective treatments for DLBCL patients.

Targeting histone deacetylase 1 (HDAC1) in the bone marrow stromal cells revers imatinib resistance by modulating IL-6 in Ph + acute lymphoblastic leukemia.

Bone marrow stromal cells (BMSCs) can promote the growth of Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). Histone deacetylases (HDACs) play essential roles in the proliferation and apoptosis resistance of Ph + ALL cells. In our previous study, inhibiting histone deacetylase 1 (HDAC1) decreases the proliferation of Ph + ALL cells. However, little is known regarding how HDAC1 in BMSCs of Ph + ALL patients affects the imatinib (IM) resistance. Therefore, the present work examined the roles of HDAC1 in BMSCs. Overexpression of HDAC1 was found in BMSCs of Ph + ALL patients with IM resistance. In addition, the Ph + ALL cell line SUP-B15 was co-cultured with BMSCs after lentivirus transfection for regulating HDAC1 expression. Knockdown of HDAC1 within BMSCs elevated the IM-mediated SUP-B15 cell apoptosis, while increasing HDAC1 expression had an opposite effect. IL-6 in BMSCs, which is an important factor for the microenvironment-associated chemoresistance, showed evident up-regulation in HDAC1-upregulated BMSCs and down-regulation in HDAC1-downregulated BMSCs. While recombinant IL-6 (rIL-6) can reversed the sensitivity of SUP-B15 cells to IM induced by downregulating HDAC1 expression in BMSCs. HDAC1 showed positive regulation on IL-6 transcription and secretion. Moreover, IL-6 secretion induced by HDAC1 in BMSCs might enhance IM resistance in Ph + ALL cells. With regard to the underlying molecular mechanism, NF-κB, an important signal responsible for IL-6 transcription in BMSCs, mediated the HDAC1-regulated IL-6 expression. Collectively, this study facilitated to develop HDAC1 inhibitors based not only the corresponding direct anti-Ph + ALL activity but also the regulation of bone marrow microenvironment.

The impact of valproic acid administration: Effects on the growth of tongue cancer cells

Background: Tongue cancer represents the predominant malignancy within the oral cavity (25-40% of squamous cell carcinoma), necessitating treatment modalities such as surgery, radiotherapy, and chemotherapy. Valproic acid, an antiepileptic medication, functions as a histone deacetylase inhibitor or activator of anti-tumor signaling pathways. Objective: To deepen our understanding of the effects of valproic acid on the viability, cytotoxicity, proliferation, and migration capabilities of HSC-3 cells. Method: This study employed an in vitro laboratory approach, exposing HSC-3 cells to valproic acid. The experimental groups included a negative control with culture media devoid of valproic acid, and treatment groups exposed to valproic acid at concentrations of 145 ppm, 180 ppm, and 355 ppm, respectively. Results: Significant differences (p-value <0.05) were observed between HSC-3 cells treated with valproic acid (145 ppm, 180 ppm, and 355 ppm) and the control group in terms of viability, cytotoxicity, proliferation, and migration. Reduced cell viability, increased cytotoxicity, and decreased proliferation were noted. Migration assays indicated suppressed migration of HSC-3 cells. Conclusion: In summary, this study reveals that valproic acid exerts substantial effects on various aspects of HSC-3 cell behavior. It decreases cell viability, enhances cytotoxicity, suppresses proliferation, and inhibits cell migration. These findings highlight the potential of valproic acid as a therapeutic agent for tongue cancer by targeting crucial cellular processes involved in cancer progression. Further research and clinical trials are essential to confirm these effects and explore their application in cancer treatment strategies. Novelty/Originality of this article:: This study shows valproic acid has potential as a therapeutic agent for tongue cancer by decreasing cell viability, increasing cytotoxicity, suppressing proliferation, and inhibiting migration of HSC-3 cells. These findings introduce a new application of valproic acid as an anticancer agent, expanding the use of antiepileptic drugs. This study opens up opportunities for developing more effective tongue cancer therapies and encourages further research and clinical trials to validate these findings

Advancing therapeutic approaches for Rett syndrome: investigating trofenitide's role-a comprehensive review

Rett syndrome is a complex neurodevelopmental disorder that mainly affects girls. It involves the loss of hand skills, walking difficulties, breathing problems, seizures, and repetitive hand movements. The syndrome starts with normal development but then goes through a regression, causing significant disability. It is caused by genetic mutations in the methyl-Cpg-binding protein 2 (MECP2) gene on the X chromosome. Rett syndrome poses challenges for patients and their families, requiring comprehensive support and a multidisciplinary approach involving healthcare professionals, educators, and social support networks. Ongoing research on trofenitide in Rett syndrome focuses on understanding its optimal dosing and long-term efficacy. Recent studies have revealed its neuroprotective and neurotrophic properties, suggesting involvement in important signaling pathways for neuronal development and synaptic plasticity. Future research aims to uncover specific molecular targets and pathways influenced by trofenitide, enabling the development of more personalized treatment strategies. Additionally, exploring the synergistic effects of trofenitide with other therapies, such as histone deacetylase (HDAC) inhibitors and N-methyl D-aspartate (NMDA) receptor modulators, shows promise for improved outcomes. Precision medicine approaches utilizing molecular profiling may aid in patient stratification and the development of targeted therapies.

CAMP signaling of Bordetella adenylate cyclase toxin blocks M-CSF triggered upregulation of iron acquisition receptors on differentiating CD14+ monocytes.

Bordetella pertussis infects the upper airways of humans and disarms host defense by the potent immuno-subversive activities of its pertussis (PT) and adenylate cyclase (CyaA) toxins. CyaA action near-instantly ablates the bactericidal activities of sentinel CR3-expressing myeloid phagocytes by hijacking cellular signaling pathways through the unregulated production of cAMP. Moreover, CyaA-elicited cAMP signaling also inhibits the macrophage colony-stimulating factor (M-CSF)-induced differentiation of incoming inflammatory monocytes into bactericidal macrophages. We show that CyaA/cAMP signaling via protein kinase A (PKA) downregulates the M-CSF-elicited expression of monocyte receptors for transferrin (CD71) and hemoglobin-haptoglobin (CD163), as well as the expression of heme oxygenase-1 (HO-1) involved in iron liberation from internalized heme. The impact of CyaA action on CD71 and CD163 levels in differentiating monocytes is largely alleviated by the histone deacetylase inhibitor trichostatin A (TSA), indicating that CyaA/cAMP signaling triggers epigenetic silencing of genes for micronutrient acquisition receptors. These results suggest a new mechanism by which B. pertussis evades host sentinel phagocytes to achieve proliferation on airway mucosa.IMPORTANCETo establish a productive infection of the nasopharyngeal mucosa and proliferate to sufficiently high numbers that trigger rhinitis and aerosol-mediated transmission, the pertussis agent Bordetella pertussis deploys several immunosuppressive protein toxins that compromise the sentinel functions of mucosa patrolling phagocytes. We show that cAMP signaling elicited by very low concentrations (22 pM) of Bordetella adenylate cyclase toxin downregulates the iron acquisition systems of CD14+ monocytes. The resulting iron deprivation of iron, a key micronutrient, then represents an additional aspect of CyaA toxin action involved in the inhibition of differentiation of monocytes into the enlarged bactericidal macrophage cells. This corroborates the newly discovered paradigm of host defense evasion mechanisms employed by bacterial pathogens, where manipulation of cellular cAMP levels blocks monocyte to macrophage transition and replenishment of exhausted phagocytes, thereby contributing to the formation of a safe niche for pathogen proliferation and dissemination.

CGRP promotes osteogenic differentiation by regulating macrophage M2 polarization through HDAC6/AKAP12 signaling pathway.

Aim: To determine the mechanism of Calcitonin gene-related peptide (CGRP) in bone healing. Materials & methods: Alkaline phosphatase (ALP) activity and inflammatory-factor levels were detected usingELISA. Osteogenic differentiation was assessed using Alizarin red staining technique. The interaction between histone deacetylase 6 (HDAC6) and A-kinase anchoring protein 12 (AKAP12) was investigated through Co- immunoprecipitation. Results: CGRP treatment promoted rat bone marrow-derived macrophages (BMDMs) M2 polarization. CGRP facilitated osteogenic differentiation by enhancing M2 polarization of BMDMs. Mechanistically, CGRP promoted AKAP12 acetylation to activate the extracellular regulated protein kinases pathway by HDAC6 inhibition. Conclusion: CGRP promoted M2 polarization of rat BMDMs and facilitated osteogenic differentiation through the HDAC6/AKAP12/extracellular regulated protein kinases signaling pathway, thereby promoting bone healing.

Effects of Etanercept on Experimental Osteoarthritis in Rats: Role of Histone Deacetylases.

Mounting evidence suggests that histone deacetylases (HDAC) inhibitors reduce cartilage destruction in animal models of osteoarthritis (OA). Tumor necrosis factor (TNF)-α-blocking treatment for OA may provide effective joint protection by slowing joint damage. To investigate the effects of intraperitoneal administration of etanercept (a TNF-α inhibitor) on OA development in rats and changes in the nociceptive behavior of rats and expression of HDACs, RUNX2, and MMP13 in cartilage. Induction of OA in Wistar rats was accomplished through anterior cruciate ligament transection (ACLT). One or five milligrams (mg) of etanercept was administered intraperitoneally for 5 consecutive weeks after ACLT to the ACLT + etanercept (1 and 5 mg/kg) groups. Nociceptive behavior and changes in knee joint width were analyzed. Cartilage was evaluated histologically and immunohistochemically. ACLT + etanercept significantly improved mechanical allodynia and weight-bearing distribution compared to ACLT alone. In OA rats treated with etanercept, cartilage degeneration and synovitis were significantly less pronounced than those in ACLT rats. OA-affected cartilage also showed reduced expression of HDAC 6, 7, RUNX-2, and MMP-13 in response to etanercept but increased expression of HDAC4. Our study demonstrated that etanercept therapy (1) attenuated the development of OA and synovitis in rats, (2) reduced nociception, and (3) regulated chondrocyte metabolism, possibly by inhibiting cell HDAC6 and HDAC7, RUNX2, and MMP13 and increasing HDAC4 expression. Based on new evidence, etanercept may have therapeutic potential in OA.

A Comprehensive Review on Novel Pathways in Cancer Treatment: Clinical Applications and Future Prospects.

Cancer is a global health issue that requires ongoing therapeutic advances. This review provides an overview of recent treatment strategies focusing on novel pathways in cancer therapy. Emerging research has unveiled promising targets that go beyond traditional modalities, offering new avenues for precision medicine and improved patient outcomes. One key area of innovation lies in targeted therapies directed at specific molecular pathways implicated in cancer progression. The identification of novel biomarkers has paved the way for the development of precision medicines tailored to individual patient profiles. Immunotherapy has also revolutionised cancer treatment by using the immune system to identify and remove cancer cells. Moreover, advancements in epigenetic therapies and RNA-based interventions demonstrate unprecedented potential in modulating gene expression and disrupting cancer-specific signalling pathways. We have discussed the pathophysiology of cancer, different immune checkpoint inhibitors, and targeted therapies in signalling therapies. The epigenetic modulators, such as Histone deacetylase (HDACs) inhibitors and DNA methyltransferase (DNMT) inhibitors, were studied. Recent breakthroughs in cancer immunotherapy treatment (CAR-T) cell therapy showcase the potential to enhance the immune response against various cancers; thus, related information was incorporated. Further, RNA-based therapies like RNA interference and mRNA-based vaccines and therapies, combination therapies, and novel therapies were discussed in the present article.