CREB-binding Protein Research Articles

MicroRNA‑4327 regulates TGF‑β1 stimulation of matrix metalloproteinase‑13 expression via CREB‑binding protein‑mediated Runx2 acetylation in human osteoblasts.

Transforming growth factor beta 1 (TGF-β1), a multifunctional cytokine, induces the expression of bone remodeling gene matrix metalloproteinase-13 (MMP-13). CREB-binding protein (CBP), a co-activator and runt-related transcription factor 2 (Runx2), a bone transcription factor, play critical roles in regulating bone-remodeling genes. Recent advances in non-coding RNAs have revealed the significance of microRNAs (miRNAs) and their target genes in bone physiology. The present study hypothesized that TGF-β1 stimulated MMP-13 expression by downregulating CBP-targeting miRNAs and activating CBP-mediated Runx2 acetylation in human osteoblastic cells. TGF-β1-downregulated miRNAs that potentially target CBP were identified. Among these miRNAs, TGF-β1 significantly downregulated miR-4327 in these cells. TGF-β1 stimulated CBP, acetylated Runx2 and MMP-13 protein expression levels in human osteoblastic cells and this effect was decreased by overexpressing miR-4327 in these cells. In human osteoblastic cells, miR-4327 was found to directly bind to the 3'-untranslated region of CBP using a dual-luciferase gene reporter assay. Thus, the present study indicated that the TGF-β1/miR-4327/CBP/Runx2 plays a key role in MMP-13 expression, suggesting the clinical relevance of this axis for treating bone-related disorders.

Childhood acute lymphoblastic leukemia with CREBBP gene mutation: a clinical analysis of 14 cases

To investigate the clinical features and prognosis of childhood acute lymphoblastic leukemia (ALL) with CREBBP gene mutation. A retrospective analysis was performed for the clinical data of 14 ALL children with CREBBP gene mutation who were admitted to Children's Hospital of the First Affiliated Hospital of Zhengzhou University from January 2016 to December 2023. The ALL patients with CREBBP gene mutation accounted for 1.5% (14/963) among all children diagnosed with ALL during the same period of time, among whom there were 4 boys (29%) and 10 girls (71%), with a median age of 4 years and 3.5 months. All children had an immunological type of B-cell ALL and concurrent mutations in other genes including NRAS, KRAS, ETV6, FLT3, PAX5, SH2B3, CDKN2A, and CDKN2B, and 4 children had karyotype abnormality. All 14 children received induction therapy with the VDLP regimen, with a complete remission (CR) rate of 79% (11/14) after the first course of treatment. Three children experienced bone marrow recurrence alone, with a recurrence rate of 21% (3/14), among whom 1 child achieved CR after blinatumomab therapy and 2 received bridging hematopoietic stem cell transplantation after chemotherapy for recurrence. Among the 14 children, 1 died due to treatment discontinuation and 13 achieved disease-free survival. The 5-year overall survival rate was 92%±7%, and the event-free survival rate was 73%±13%. ALL with CREBBP gene mutation is more common in girls and has a low induction remission rate and a high recurrence rate, and it is often accompanied by other types of gene mutations and abnormal karyotypes. Most children with recurrence can achieve long-term survival after immunotherapy or hematopoietic stem cell transplantation.

FXR deficiency induced ferroptosis via modulation of the CBP-dependent p53 acetylation to suppress breast cancer growth and metastasis

Farnesoid X receptor (NR1H4/FXR) functions as a scavenger of lipid peroxide products and drives the proliferation and metastasis of various cancers. However, the underlying molecular mechanisms remain poorly understood. In our study, we found that the expression levels of FXR, vimentin and SLC7A11 were significantly higher in breast cancer tissues, particularly in metastatic cancer tissues compared to non-metastatic ones. Furthermore, the increased FXR expression was positively correlated with vimentin and SLC7A11 in clinical tumor specimens. In addition, a high level of FXR correlated with poor prognosis in patients with breast cancer. Both Z-Guggulsterone (Z-GS), as a pharmacological inhibitor of FXR, and silencing FXR curbed proliferation and migration of breast cancer cells by promoting ferroptosis. Notably, our results showed that FXR competitively bound to CREB-binding protein (CBP) to suppress the interaction between p53 and CBP in the nucleus, and thus prevented p53 acetylation at lys382, which was essential for upregulating the expression of SLC7A11. Conversely, FXR knockdown increased the interaction between p53 and CBP and promoted p53 acetylation, which ultimately led to facilitating ferroptosis in breast cancer cells. More importantly, we also found that Z-GS inhibited TGF-β1-induced tumor growth and metastasis of breast cancer primarily through ferroptosis via regulating CBP-dependent p53 acetylation in nude mice. In conclusion, the FXR was first reported as a tumor promoter that enhanced the proliferation and metastasis of breast cancer cells through regulating CBP-dependent p53 K382 acetylation. It proposes that FXR may serve as a potential therapeutic target for the treatment of breast cancer.

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

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

Solid-basaloid Variant of Mammary Adenoid Cystic Carcinoma – Report of an Unusual Case with Literature Review

Abstract Introduction/Objective Adenoid cystic carcinoma (AdCC) of breast is a rare subtype of malignancy, constituting approximately 0.1% of all breast carcinomas. The solid-basaloid variant (SB-AdCC) is exceedingly uncommon. Here, we present such an unusual case of SB-AdCC. Methods/Case Report A 64-year-old woman who underwent screening mammography presented with abnormal findings, revealing a hypoechoic ovoid, lobulated nodule at 7:00 of the left breast, which prompted an ultrasound- guided biopsy. Histologically, the biopsy cores demonstrated a 9 mm infiltrative round, solid nests with focal “cribriforming” areas. It was composed of monomorphic basaloid epithelial cells with marked nuclear atypia and high mitotic count. High-grade ductal carcinoma in situ, solid papillary carcinoma, and nonspecific invasive carcinoma were in differentials. Immunohistochemical (IHC) staining expressed positivity for CD117 and CK 5/6, while p63, SMMHC, and synaptophysin were negative. MYB gene rearrangement confirmed by fluorescence in situ hybridization. As expected, the tumor lacked ER, PR, and HER2 expression by IHC. Left breast mastectomy and axillary lymph node dissection have been scheduled. Results (if a Case Study enter NA) NA Conclusion Per literature review, the mean age of SB-AdCC at diagnosis was 68 years (33-84 years) with an average tumor size of 25 mm (12-70 mm). It had more aggressive behavior, with a higher propensity for lymph node metastasis, locally recurrence, and distant metastasis. The median disease-free survival was 46.5 months versus 151.8 months in those with class AdCC. Notably, neovascularization has emerged as a strong independent predictor of outcome in SB-AdCC. Most patients were treated with surgical excision, axillary lymph node dissection, and/or adjuvant chemotherapy. Limited studies demonstrated that neoadjuvant chemotherapy may induce an excellent response. Furthermore, a distinct molecular mutation enriched in NOTCH and CREBBP genes has been identified, which could be novel potential therapeutic target. Thus, awareness of this extremely rare breast cancer subtype and accurate differentiation from other entities are paramount for appropriate management strategies.

BCKDH kinase promotes hepatic gluconeogenesis independent of BCKDHA

Elevated circulating branched-chain amino acids (BCAAs) are tightly linked to an increased risk in the development of type 2 diabetes mellitus. The rate limiting enzyme of BCAA catabolism branched-chain α-ketoacid dehydrogenase (BCKDH) is phosphorylated at E1α subunit (BCKDHA) by its kinase (BCKDK) and inactivated. Here, the liver-specific BCKDK or BCKDHA knockout mice displayed normal glucose tolerance and insulin sensitivity. However, knockout of BCKDK in the liver inhibited hepatic glucose production as well as the expression of key gluconeogenic enzymes. No abnormal gluconeogenesis was found in mice lacking hepatic BCKDHA. Consistent with the vivo results, BT2-mediated inhibition or genetic knockdown of BCKDK decreased hepatic glucose production and gluconeogenic gene expressions in primary mouse hepatocytes while BCKDK overexpression exhibited an opposite effect. Whereas, gluconeogenic gene expressions were not altered in BCKDHA-silenced hepatocytes. Mechanistically, BT2 treatment attenuated the interaction of cAMP response element binding protein (CREB) with CREB-binding protein and promoted FOXO1 protein degradation by increasing its ubiquitination. Our findings suggest that BCKDK regulates hepatic gluconeogenesis through CREB and FOXO1 signalings, independent of BCKDHA-mediated BCAA catabolism.

Comparative proteomic analysis of regenerative mechanisms in mouse retina to identify markers for neuro-regeneration in glaucoma

The retina is part of the central nervous system (CNS). Neurons in the CNS and retinal ganglion cells lack the ability to regenerate axons spontaneously after injury. The intrinsic axonal growth regulators, their interaction and roles that enable or inhibit axon growth are still largely unknown. This study endeavored to characterize the molecular characteristics under neurodegenerative and regenerative conditions. Data-Independent Acquisition Mass Spectrometry was used to map the comprehensive proteome of the regenerative retina from 14-day-old mice (Reg-P14) and adult mice after lens injury (Reg-LI) both showing regrowing axons in vitro, untreated adult mice, and retina from adult mice subjected to two weeks of elevated intraocular pressure showing degeneration. A total of 5750 proteins were identified (false discovery rate < 1%). Proteins identified in both Reg-P14 and Reg-LI groups were correlated to thyroid hormone, Notch, Wnt, and VEGF signaling pathways. Common interactors comprising E1A binding protein P300 (EP300), CREB binding protein (CBP), calcium/calmodulin dependent protein kinase II alpha (CaMKIIα) and sirtuin 1 (SIRT1) were found in both Reg-P14 and Reg-LI retinas. Proteins identified in both regenerating and degenerative groups were correlated to thyroid hormone, Notch, mRNA surveillance and measles signaling pathways, along with PD-L1 expression and the PD-1 checkpoint pathway. Common interactors across regenerative and degenerative retinas comprising NF-kappa-B p65 subunit (RELA), RNA-binding protein with serine-rich domain 1 (RNPS1), EP300 and SIN3 transcription regulator family member A (SIN3A). The findings from our study provide the first mapping of regenerative mechanisms across postnatal, mature and degenerative mouse retinas, revealing potential biomarkers that could facilitate neuro-regeneration in glaucoma.

Targeting CREB-binding protein (CBP) abrogates colorectal cancer stemness through epigenetic regulation of C-MYC.

Colorectal cancer (CRC) is a common cancer worldwide with an increasing annual incidence. Cancer stem cells (CSCs) play important roles in the occurrence, development, recurrence, and metastasis of CRC. The molecular mechanism regulating the development of colorectal CSCs remains unclear. The discovery of human induced pluripotent stem cells (hiPSCs) through somatic cell reprogramming has revolutionized the fields of stem cell biology and translational medicine. In the present study, we converted hiPSCs into cancer stem-like cells by culture with conditioned medium (CM) from CRC cells. These transformed cells, termed hiPSC-CSCs, displayed cancer stem-like properties, including a spheroid morphology and the expression of both pluripotency and CSC markers. HiPSC-CSCs showed tumorigenic and metastatic abilities in mouse models. The epithelial-mesenchymal transition phenotype was observed in hiPSC-CSCs, which promoted their migration and angiogenesis. Interestingly, upregulation of C-MYC was observed during the differentiation of hiPSC-CSCs. Mechanistically, CREB binding protein (CBP) bound to the C-MYC promoter, while histone deacetylase 1 and 3 (HDAC1/3) dissociated from the promoter, ultimately leading to an increase in histone acetylation and C-MYC transcriptional activation during the differentiation of hiPSC-CSCs. Pharmacological treatment with a CBP inhibitor or abrogation of CBP expression with a CRISPR/Cas9-based strategy reduced the stemness of hiPSC-CSCs. This study demonstrates for the first time that colorectal CSCs can be generated from hiPSCs. The upregulation of C-MYC via histone acetylation plays a crucial role during the conversion process. Inhibition of CBP is a potential strategy for attenuating the stemness of colorectal CSCs.

Discovery of CZL-046 with an (S)-3-Fluoropyrrolidin-2-one Scaffold as a p300 Bromodomain Inhibitor for the Treatment of Multiple Myeloma.

E1A binding protein (p300) is a promising therapeutic target for the treatment of cancer. Herein, we report the discovery of a series of novel inhibitors with an (S)-3-fluoropyrrolidin-2-one scaffold targeting p300 bromodomain. The best compound 29 (CZL-046) shows potent inhibitory activity of p300 bromodomain (IC50 = 3.3 nM) and antiproliferative activity in the multiple myeloma (MM) cell line (OPM-2 IC50 = 51.5 nM). 29 suppressed the mRNA levels of c-Myc and IRF4 and downregulated the expression of c-Myc and H3K27Ac. Compared to the lead compound 5, 29 exhibits significantly improved in vitro and in vivo metabolic properties. Oral administration of 29 with 30 mg/kg achieved a TGI value of 44% in the OPM-2 xenograft model, accompanied by good tolerability. The cocrystal structure of CREB binding protein bromodomain with 29 provides an insight into the precise binding mode. The results demonstrate that 29 is a promising p300 bromodomain inhibitor for the treatment of MM.

AJS-2 Targeting Wnt/β-catenin signaling: E7386, an orally active selective inhibitor of the interaction between β-catenin and CREB-binding protein (CBP)

AJS-2 Targeting Wnt/β-catenin signaling: E7386, an orally active selective inhibitor of the interaction between β-catenin and CREB-binding protein (CBP)

PBA2, a novel inhibitor of the β-catenin/CBP pathway, eradicates chronic myeloid leukemia including BCR-ABL T315I mutation

BackgroundBCR-ABL is a constitutively active tyrosine kinase that stimulates multiple downstream signaling pathways to promote the survival and proliferation of chronic myeloid leukemia (CML) cells. The clinical application of specific BCR-ABL tyrosine kinase inhibitors (TKIs) has led to significantly improved prognosis and overall survival in CML patients compared to previous treatment regimens. However, direct targeting of BCR-ABL does not eradicate CML cells expressing T315I-mutated BCR-ABL. Our previous study revealed that inhibiting CREB binding protein (CBP) is efficacious in activating β-catenin/p300 signaling, promoting cell differentiation and inducing p53/p21-dependent senescence regardless of BCR-ABL mutation status. We hypothesize that the specific inhibition of CBP may represent a novel strategy to promote β-catenin/p300-mediated differentiation and suppress cancer cell proliferation for treating CML patients.MethodsThe anticancer efficacy of PBA2, a novel CBP inhibitor, in CML cells expressing wild-type or T315I-mutated BCR-ABL was investigated in vitro and in vivo. Cell differentiation was determined by the nitroblue tetrazolium (NBT) reduction assay. The extent of cellular senescence was assessed by senescence-associated β-galactosidase (SA-β-Gal) activity. Cytotoxicity was measured by MTS assay. RNA interference was performed to evaluate the cell proliferation effects of CBP knockdown. The interaction of β-catenin and CBP/p300 was examined by co-immunoprecipitation assay.ResultsPBA2 exhibited significantly higher anticancer effects than imatinib in CML cells harboring either wild-type or T315I-mutated BCR-ABL both in vitro and in vivo. Mechanistically, PBA2 reduced CBP expression and promoted β-catenin-p300 interaction to induce cell differentiation and senescence.ConclusionOur data supported the rational treatment of CML by inhibiting the β-catenin/CBP pathway regardless of BCR-ABL mutation status.

CREB-binding protein/P300 bromodomain inhibition reduces neutrophil accumulation and activates antitumor immunity in triple-negative breast cancer.

Tumor-associated neutrophils (TANs) have been shown to promote immunosuppression and tumor progression, and a high TAN frequency predicts poor prognosis in triple-negative breast cancer (TNBC). Dysregulation of CREB-binding protein (CBP)/P300 function has been observed with multiple cancer types. The bromodomain (BRD) of CBP/P300 has been shown to regulate its activity. In this study, we found that IACS-70654, a selective CBP/P300 BRD inhibitor, reduced TANs and inhibited the growth of neutrophil-enriched TNBC models. In the bone marrow, CBP/P300 BRD inhibition reduced the tumor-driven abnormal differentiation and proliferation of neutrophil progenitors. Inhibition of CBP/P300 BRD also stimulated the immune response by inducing an IFN response and MHCI expression in tumor cells and increasing tumor-infiltrated cytotoxic T cells. Moreover, IACS-70654 improved the response of a neutrophil-enriched TNBC model to docetaxel and immune checkpoint blockade. This provides a rationale for combining a CBP/P300 BRD inhibitor with standard-of-care therapies in future clinical trials for neutrophil-enriched TNBC.

Zinc-finger CCHC-type containing protein 8 promotes RNA virus replication by suppressing the type-I interferon responses.

Host cells have evolved an intricate regulatory network to fine tune the type-I interferon responses. However, the full picture of this regulatory network remains to be depicted. In this study, we found that knock out of zinc-finger CCHC-type containing protein 8 (ZCCHC8) impairs the replication of influenza A virus (IAV), Sendai virus (Sev), Japanese encephalitis virus (JEV), and vesicular stomatitis virus (VSV). Further investigation unveiled that ZCCHC8 suppresses the type-I interferon responses by targeting the interferon regulatory factor 3 (IRF3) signaling pathway. Mechanistically, ZCCHC8 associates with phosphorylated IRF3 and disrupts the interaction of IRF3 with the co-activator CREB-binding protein (CBP). Additionally, the direct binding of ZCCHC8 with the IFN-stimulated response element (ISRE) impairs the ISRE-binding of IRF3. Our study contributes to the comprehensive understanding for the negative regulatory network of the type-I interferon responses and provides valuable insights for the control of multiple viruses from a host-centric perspective.IMPORTANCEThe innate immune responses serve as the initial line of defense against invading pathogens and harmful substances. Negative regulation of the innate immune responses plays an essential role in avoiding auto-immune diseases and over-activated immune responses. Hence, the comprehensive understanding of the negative regulation network for innate immune responses could provide novel therapeutic insights for the control of viral infections and immune dysfunction. In this study, we report that ZCCHC8 negatively regulates the type-I interferon responses. We illustrate that ZCCHC8 impedes the IRF3-CBP association by interacting with phosphorylated IRF3 and competes with IRF3 for binding to ISRE. Our study demonstrates the role of ZCCHC8 in the replication of multiple RNA viruses and contributes to a deeper understanding of the negative regulation system for the type-I interferon responses.

Inhibition of Renin Expression Is Regulated by an Epigenetic Switch From an Active to a Poised State.

Renin-expressing cells are myoendocrine cells crucial for the maintenance of homeostasis. Renin is regulated by cAMP, p300 (histone acetyltransferase p300)/CBP (CREB-binding protein), and Brd4 (bromodomain-containing protein 4) proteins and associated pathways. However, the specific regulatory changes that occur following inhibition of these pathways are not clear. We treated As4.1 cells (tumoral cells derived from mouse juxtaglomerular cells that constitutively express renin) with 3 inhibitors that target different factors required for renin transcription: H-89-dihydrochloride, PKA (protein kinase A) inhibitor; JQ1, Brd4 bromodomain inhibitor; and A-485, p300/CBP inhibitor. We performed assay for transposase-accessible chromatin with sequencing (ATAC-seq), single-cell RNA sequencing, cleavage under targets and tagmentation (CUT&Tag), and chromatin immunoprecipitation sequencing for H3K27ac (acetylation of lysine 27 of the histone H3 protein) and p300 binding on biological replicates of treated and control As4.1 cells. In response to each inhibitor, Ren1 expression was significantly reduced and reversible upon washout. Chromatin accessibility at the Ren1 locus did not markedly change but was globally reduced at distal elements. Inhibition of PKA led to significant reductions in H3K27ac and p300 binding specifically within the Ren1 super-enhancer region. Further, we identified enriched TF (transcription factor) motifs shared across each inhibitory treatment. Finally, we identified a set of 9 genes with putative roles across each of the 3 renin regulatory pathways and observed that each displayed differentially accessible chromatin, gene expression, H3K27ac, and p300 binding at their respective loci. Inhibition of renin expression in cells that constitutively synthesize and release renin is regulated by an epigenetic switch from an active to poised state associated with decreased cell-cell communication and an epithelial-mesenchymal transition. This work highlights and helps define the factors necessary for renin cells to alternate between myoendocrine and contractile phenotypes.

Changes in the molecular nodes of the Notch and NRF2 pathways in cervical cancer tissues from the precursor stages to invasive carcinoma.

Cancer is a multifactorial disease characterized by the loss of control in the expression of genes known as cancer driver genes. Cancer driver genes trigger uncontrolled cell replication, which leads to the development of malignant tumors. A cluster of signal transduction pathways that contain cancer driver genes involved in cellular processes, such as cell proliferation, differentiation, apoptosis and dysregulated organ growth, are associated with cancer initiation and progression. In the present study, three signal transduction pathways involved in cervical cancer (CC) development were analyzed: The Hippo pathway (FAT atypical cadherin, yes-associated protein 1, SMAD4 and TEA domain family member 2), the Notch pathway [cellular-MYC, cAMP response element-binding binding protein (CREBBP), E1A-associated cellular p300 transcriptional co-activator protein and F-Box and WD repeat domain containing 7] and the nuclear factor erythroid 2-related factor 2 (NRF2) pathway [NRF2, kelch-like ECH-associated protein 1 (KEAP1), AKT and PIK3-catalytic subunit α]. Tumor samples from patients diagnosed with various stages of CC, including cervical intraepithelial neoplasia (CIN) 1, CIN 2, CIN 3, in situ CC and invasive CC, were analyzed. The mRNA expression levels were analyzed using reverse transcription-quantitative PCR assays, whereas protein expression levels were assessed through immunohistochemical tissue microarrays. High mRNA expression levels of c-MYC and AKT and low expression levels of NRF2 and KEAP1 were associated with a decreased survival time of patients with CC. Additionally, increased expression levels of c-MYC were detected in the invasive CC stage. At the protein level, increased NRF2 expression levels were observed in all five stages of CC samples compared with those in the cancer-free control samples. AKT1 was found to be dysregulated in the CIN 1 and CIN 2 stages, PI3K in the in situ and invasive stages, and CREBBP in the CIN 3 and in situ stages. In summary, the present study demonstrated significant changes in proteins of the Notch and NRF2 pathways in CC. NRF2 was overexpressed in all cervical cancer stages (cervical intraepithelial neoplasia, in situ CC and invasive CC). The present study makes an important contribution to the possible biomarker proteins to be analyzed for the presence of premalignant and malignant lesions in the cervix.

Microtubules Sequester Acetylated YAP in the Cytoplasm and Inhibit Heart Regeneration.

The Hippo pathway effector YAP (Yes-associated protein) plays an essential role in cardiomyocyte proliferation and heart regeneration. In response to physiological changes, YAP moves in and out of the nucleus. The pathophysiological mechanisms regulating YAP subcellular localization after myocardial infarction remain poorly defined. We identified YAP acetylation at site K265 by in vitro acetylation followed by mass spectrometry analysis. We used adeno-associated virus to express YAP-containing mutations that either abolished acetylation (YAP-K265R) or mimicked acetylation (YAP-K265Q) and studied how acetylation regulates YAP subcellular localization in mouse hearts. We generated a cell line with YAP-K265R mutation and investigated the protein-protein interactors by YAP immunoprecipitation followed by mass spectrometry, then validated the YAP interaction in neonatal rat ventricular myocytes. We examined colocalization of YAP and TUBA4A (tubulin α 4A) by superresolution imaging. Furthermore, we developed YAP-K265R and αMHC-MerCreMer (MCM); Yap-loxP/K265R mutant mice to examine the pathophysiological role of YAP acetylation in cardiomyocytes during cardiac regeneration. We found that YAP is acetylated at K265 by CBP (CREB-binding protein)/P300 (E1A-binding protein P300) and is deacetylated by nicotinamide phosphoribosyltransferase/nicotinamide adenine dinucleotide/sirtuins axis in cardiomyocytes. After myocardial infarction, YAP acetylation is increased, which promotes YAP cytoplasmic localization. Compared with controls, mice that were genetically engineered to express a K265R mutation that prevents YAP K256 acetylation showed improved cardiac regenerative ability and increased YAP nuclear localization. Mechanistically, YAP acetylation facilitates its interaction with TUBA4A, a component of the microtubule network that sequesters acetylated YAP in the cytoplasm. After myocardial infarction, the microtubule network increased in cardiomyocytes, resulting in the accumulation of YAP in the cytoplasm. After myocardial infarction, decreased sirtuin activity enriches YAP acetylation at K265. The growing TUBA4A network sequesters acetylated YAP within the cytoplasm, which is detrimental to cardiac regeneration.

Maintenance of thermogenic adipose tissues despite loss of the H3K27 acetyltransferases p300 or CBP.

Brown and beige adipose tissues are specialized for thermogenesis and are important for energy balance in mice. Mounting evidence suggests that chromatin-modifying enzymes are integral for the development, maintenance, and functioning of thermogenic adipocytes. p300 and cAMP-response element binding protein (CREB)-binding protein (CBP) are histone acetyltransferases (HATs) responsible for writing the transcriptionally activating mark H3K27ac. Despite their homology, p300 and CBP do have unique tissue- and context-dependent roles, which have yet to be examined in brown and beige adipocytes specifically. We assessed the requirement of p300 or CBP in thermogenic fat using uncoupling protein 1 (Ucp1)-Cre-mediated knockdown in mice to determine whether their loss impacted tissue development, susceptibility to diet-induced obesity, and response to pharmacological induction via β3-agonism. Despite successful knockdown, brown adipose tissue mass and expression of thermogenic markers were unaffected by loss of either HAT. As such, knockout mice developed a comparable degree of diet-induced obesity and glucose intolerance to that of floxed controls. Furthermore, "browning" of white adipose tissue by the β3-adrenergic agonist CL-316,243 remained largely intact in knockout mice. Although p300 and CBP have nonoverlapping roles in other tissues, our results indicate that they are individually dispensable within thermogenic fats specifically, possibly due to functional compensation by one another.NEW & NOTEWORTHY The role of transcriptionally activating H3K27ac epigenetic mark has yet to be examined in mouse thermogenic fats specifically, which we achieved here via Ucp1-Cre-driven knockdown of the histone acetyltransferases (HAT) p300 or CBP under several metabolic contexts. Despite successful knockdown of either HAT, brown adipose tissue was maintained at room temperature. As such, knockout mice were indistinguishable to controls when fed an obesogenic diet or when given a β3-adrenergic receptor agonist to induce browning of white fat. Unlike other tissues, thermogenic fats are resilient to p300 or CBP ablation, likely due to sufficient functional overlap between them.

Prenatal diagnosis of a fetus with Rubinstein-Taybi syndrome

To explore the clinical characteristics and variant of CREBBP gene in a fetus with Rubinstein-Taybi syndrome (RSTS). A fetus with RSTS diagnosed at the Third Affiliated Hospital of Zhengzhou University in August 2022 was selected as the study subject. Clinical data, amniotic fluid sample of the fetus and peripheral blood samples of its parents were collected for whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing. Foot malformation, cerebellar vermis agenesis, brain agenesis, polysyndactyly of the big toes and other phenotypes were found by prenatal ultrasound. WES revealed that the fetus has harbored a heterozygous c.4684G>T (p.E1562*) variant in exon 28 of the CREBBP gene (NM_004380.3), which was de novo in origin. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was predicted to be pathogenic (PVS1+PS2_Moderate+PM2_Supporting). After genetic counseling, the couple had opted to terminate the pregnancy and refused autopsy of the fetus. The c.4684G>T (p.E1562*) variant of the CREBBP gene probably underlay the RSTS in this fetus. The newly discovered variant has enriched the mutational spectrum of the CREBBP gene and illustrated that WES is an efficient tool for the prenatal diagnosis of RSTS.

Structure-Based Design of CBP/EP300 Degraders: When Cooperativity Overcomes Affinity.

We present the development of dCE-2, a structurally novel PROTAC targeting the CREB-binding protein (CBP) and E1A-associated protein (EP300)-two homologous multidomain enzymes crucial for enhancer-mediated transcription. The design of dCE-2 was based on the crystal structure of an in-house bromodomain (BRD) inhibitor featuring a 3-methyl-cinnoline acetyl-lysine mimic acetyl-lysine mimic discovered by high-throughput fragment docking. Our study shows that, despite its modest binding affinity to CBP/EP300-BRD, dCE-2's remarkable protein degradation activity stems from its good cooperativity, which we demonstrate by the characterization of its ternary complex formation both in vitro and in cellulo. Molecular dynamics simulations indicate that in aqueous solvents, this active degrader populates both folded and extended conformations, which are likely to promote cell permeability and ternary complex formation, respectively.

Lefamulin Overcomes Acquired Drug Resistance via Regulating Mitochondrial Homeostasis by Targeting ILF3 in Hepatocellular Carcinoma.

Acquired resistance represents a critical clinical challenge to molecular targeted therapies such as tyrosine kinase inhibitors (TKIs) treatment in hepatocellular carcinoma (HCC). Therefore, it is urgent to explore new mechanisms and therapeutics that can overcome or delay resistance. Here, a US Food and Drug Administration (FDA)-approved pleuromutilin antibiotic is identified that overcomes sorafenib resistance in HCC cell lines, cell line-derived xenograft (CDX) and hydrodynamic injection mouse models. It is demonstrated that lefamulin targets interleukin enhancer-binding factor 3 (ILF3) to increase the sorafenib susceptibility of HCC via impairing mitochondrial function. Mechanistically, lefamulin directly binds to the Alanine-99 site of ILF3 protein and interferes with acetyltransferase general control non-depressible 5 (GCN5) and CREB binding protein (CBP) mediated acetylation of Lysine-100 site, which disrupts the ILF3-mediated transcription of mitochondrial ribosomal protein L12 (MRPL12) and subsequent mitochondrial biogenesis. Clinical data further confirm that high ILF3 or MRPL12 expression is associated with poor survival and targeted therapy efficacy in HCC. Conclusively, this findings suggest that ILF3 is a potential therapeutic target for overcoming resistance to TKIs, and lefamulin may be a novel combination therapy strategy for HCC treatment with sorafenib and regorafenib.