The poly(ADP-ribosyl)ation of BRD4 mediated by PARP1 promoted pathological cardiac hypertrophy

Up-regulation of BRD4 contributes to gestational diabetes mellitus-induced cardiac hypertrophy in offspring by promoting mitochondria dysfunction in sex-independent manner

Gestational diabetes mellitus (GDM) is associated with cardiovascular disease in postnatal life. The current study tested the hypothesis that GDM caused the cardiac hypertrophy in fetal (ED18.5), postnatal day 7 (PD7), postnatal day 21 (PD21) and postnatal day 90 (PD90) offspring by upregulation of BRD4 and mitochondrial dysfunction. Pregnant mice were divided into control and GDM groups. Hearts were isolated from ED18.5, PD7, PD21 and PD90. GDM increased the body weight (BW) and heart weight (HW) in ED18.5 and PD7, but not PD21 and PD90 offspring. However, HW/BW ratio was increased in all ages of GDM offspring compared to control group. Electron microscopy showed disorganized myofibrils, mitochondrial swelling, vacuolization, and cristae disorder in GDM offspring. GDM resulted in myocardial hypertrophy in offspring, which persisted from fetus to adult in a sex-independent manner. Echocardiography analysis revealed that GDM caused diastolic dysfunction, but had no effect on systolic function. Meanwhile, myocardial BRD4 was significantly upregulated in GDM offspring and BRD4 inhibition by JQ1 alleviated GDM-induced myocardial hypertrophy in offspring. Co-immunoprecipitation showed that BRD4 interacted with DRP1 and there was an increase of BRD4 and DRP1 interaction in GDM offspring. Furthermore, GDM caused the accumulation of damaged mitochondria in hearts from all ages of offspring, including mitochondrial fusion fission imbalance (upregulation of DRP1, and downregulation of MFN1, MFN2 and OPA1) and myocardial mitochondrial ROS accumulation, which was reversed by JQ1. These results suggested that the upregulation of BRD4 is involved in GDM-induced myocardial hypertrophy in the offspring through promoting mitochondrial damage in a gender-independent manner.

Discovery of highly potent PARP7 inhibitors for cancer immunotherapy

PARP7 has been proven to play an important role in immunity. Substantial upregulation of PARP7 is observed in numerous cancerous cell types, consequently resulting in the inhibition of type Ⅰ interferon signaling pathways. Therefore, inhibiting the activity of PARP7 can enhance type Ⅰ interferon signaling to exert an anti-tumor immune response. In this study, we reported the identification of a newly found PARP7 inhibitor (XLY-1) with higher inhibitory activity (IC50 = 0.6 nM) than that of RBN-2397 (IC50 = 6.0 nM). Additionally, XYL-1 displayed weak inhibitory activity on PARP1 (IC50 > 1.0 μM). Mechanism studies showed that XYL-1 could enhance the type Ⅰ interferon signaling in vitro. Pharmacodynamic experiments showed that 50 mg/kg XYL-1 could significantly inhibit tumor growth (TGI: 76.5 %) and related experiments showed that XYL-1 could restore type Ⅰ interferon signaling and promote T cell infiltration in tumor tissues. Taken together, XYL-1 shows promise as a potential candidate for developing cancer immunotherapy agents.

Targeting BRD4 with PROTAC degrader ameliorates LPS-induced acute lung injury by inhibiting M1 alveolar macrophage polarization

OBJECTIVES

Acute lung injury (ALI) is a highly inflammatory condition with the involvement of M1 alveolar macrophages (AMs) polarization, eventually leading to the development of non-cardiogenic edema in alveolar and interstitial regions, accompanied by persistent hypoxemia. Given the significant mortality rate associated with ALI, it is imperative to investigate the underlying mechanisms of this condition so as to identify potential therapeutic targets. The therapeutic effects of the inhibition of bromodomain containing protein 4 (BRD4), an epigenetic reader, has been proven with high efficacy in ameliorating various inflammatory diseases through mediating immune cell activation. However, little is known about the therapeutic potential of BRD4 degradation in acute lung injury.

METHODS

This study aimed to assess the protective efficacy of ARV-825, a novel BRD4-targeted proteolysis targeting chimera (PROTAC), against ALI through histopathological examination in lung tissues and biochemical analysis in bronchoalveolar lavage fluid (BALF). Additionally, the underlying mechanism by which BRD4 regulated M1 AMs was elucidated by using CUT & Tag assay.

RESULTS

In this study, we found the upregulation of BRD4 in a lipopolysaccharide (LPS)-induced ALI model. Furthermore, we observed that intraperitoneal administration of ARV-825, significantly alleviated LPS-induced pulmonary pathological changes and inflammatory responses. These effects were accompanied by the suppression of M1 AMs. In addition, our findings revealed that the administration of ARV-825 effectively suppressed M1 AMs by inhibiting the expression of IRF7, a crucial transcriptional factor involved in M1 macrophages.

CONCLUSION

Our study suggested that targeting BRD4 using ARV-825 is a potential therapeutic approach for ALI.

Epigenetics in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a critical complication that poses a significant threat to the health of patients with diabetes. The intricate pathological mechanisms of DCM cause diastolic dysfunction, followed by impaired systolic function in the late stages. Accumulating researches have revealed the association between DCM and various epigenetic regulatory mechanisms, including DNA methylation, histone modifications, non-coding RNAs, and other epigenetic molecules. Recently, a profound understanding of epigenetics in the pathophysiology of DCM has been broadened owing to advanced high-throughput technologies, which assist in developing potential therapeutic strategies. In this review, we briefly introduce the epigenetics regulation and update the relevant progress in DCM. We propose the role of epigenetic factors and non-coding RNAs (ncRNAs) as potential biomarkers and drugs in DCM diagnosis and treatment, providing a new perspective and understanding of epigenomics in DCM.

Discovery of Highly Selective PARP7 Inhibitors with a Novel Scaffold for Cancer Immunotherapy

PARP7 plays a crucial role in cancer immunity. The inhibition of PARP7 has shown potential in boosting the immune response against cancer, making it an attractive target for cancer immunotherapy. Herein, we employed a rigid constraint strategy (reduction in molecular flexibility) to design and synthesize a series of novel indazole-7-carboxamide derivatives based on the structure of RBN-2397. Among these derivatives, (S)-XY-05 was identified as the most promising PARP7 inhibitor (IC50: 4.5 nM). Additionally, (S)-XY-05 showed enhanced selectivity toward PARP7 and improved pharmacokinetic properties (oral bioavailability: 94.60%) compared with RBN-2397 (oral bioavailability: 25.67%). In the CT26 syngeneic mouse model, monotherapy with (S)-XY-05 displayed a strong antitumor effect (TGI: 83%) by activating T-cell-mediated immunity within the tumor microenvironment. Collectively, we confirmed that (S)-XY-05 has profound effects on tumor immunity, which paves the way for future studies of PARP7 inhibitors that could be utilized in cancer immunotherapy.

ADP-ribosylation: An emerging direction for disease treatment

ADP-ribosylation (ADPr) is a dynamically reversible post-translational modification (PTM) driven primarily by ADP-ribosyltransferases (ADPRTs or ARTs), which have ADP-ribosyl transfer activity. ADPr modification is involved in signaling pathways, DNA damage repair, metabolism, immunity, and inflammation. In recent years, several studies have revealed that new targets or treatments for tumors, cardiovascular diseases, neuromuscular diseases and infectious diseases can be explored by regulating ADPr. Here, we review the recent research progress on ART-mediated ADP-ribosylation and the latest findings in the diagnosis and treatment of related diseases.

Inhibition of Brd4 alleviates osteoarthritis pain via suppression of neuroinflammation and activation of Nrf2-mediated antioxidant signalling

BACKGROUND AND PURPOSE

Osteoarthritis (OA) pain remains a major clinical problem. It is urgent to identify novel therapeutic approaches for OA pain states. Bromodomain and extra-terminal (BET) protein inhibitors have robust anti-inflammatory effects in several pain models. However, the underlying mechanisms of these inhibitors in OA pain have not been determined. We, therefore, investigated the effects and the underlying mechanism(s) of BET inhibition on pain-related behaviours in a rat model of OA.

EXPERIMENTAL APPROACH

The OA model was established by intra-articular injection of monosodium iodoacetate (MIA) in rat knees. Pain behaviours were assessed in rats by hindlimb weight-bearing asymmetry, mechanical allodynia and thermal hyperalgesia. Possible mechanisms underlying BET inhibition were explored in the MIA-induced OA pain model in the spinal cord and dorsal root ganglia (DRG).

KEY RESULTS

Inhibiting bromodomain-containing protein 4 (Brd4) with either JQ1 or MS417, or using AAV2/9-shRNA-Brd4-EGFP-mediated knockdown of Brd4 genes, significantly attenuated MIA-induced pain behaviours. Brd4 inhibition suppressed NF-κB and NF-κB-mediated inflammatory cytokines in both the spinal cord and DRG in rats with MIA-induced OA pain. Brd4 inhibition also attenuated the oxidative stress and promoted nuclear factor erythroid-2-related factor 2 (Nrf2)-dependent antioxidant genes in both the spinal cord and DRG in our odel of MIA-induced OA pain.

CONCLUSIONS AND IMPLICATIONS

In conclusion, Brd4 inhibition alleviated MIA-induced OA pain in rats, via suppression of neuroinflammation and activation of Nrf2-mediated antioxidant signalling. Although our model does not perfectly represent how OA develops in humans, inhibition of Brd4 may provide novel insights into possible treatments for OA pain.

BRD4 and MYC: power couple in transcription and disease

The MYC proto-oncogene and BRD4, a BET family protein, are two cardinal proteins that have a broad influence in cell biology and disease. Both proteins are expressed ubiquitously in mammalian cells and play central roles in controlling growth, development, stress responses and metabolic function. As chromatin and transcriptional regulators, they play a critical role in regulating the expression of a burgeoning array of genes, maintaining chromatin architecture and genome stability. Consequently, impairment of their function or regulation leads to many diseases, with cancer being the most predominant. Interestingly, accumulating evidence indicates that regulation of the expression and functions of MYC are tightly intertwined with BRD4 at both transcriptional and post-transcriptional levels. Here, we review the mechanisms by which MYC and BRD4 are regulated, their functions in governing various molecular mechanisms and the consequences of their dysregulation that lead to disease. We present a perspective of how the regulatory mechanisms for the two proteins could be entwined at multiple points in a BRD4-MYC nexus that leads to the modulation of their functions and disease upon dysregulation.

JMJD6 protects against isoproterenol-induced cardiac hypertrophy via inhibition of NF-κB activation by demethylating R149 of the p65 subunit

Histone modification plays an important role in pathological cardiac hypertrophy and heart failure. In this study we investigated the role of a histone arginine demethylase, Jumonji C domain-containing protein 6 (JMJD6) in pathological cardiac hypertrophy. Cardiac hypertrophy was induced in rats by subcutaneous injection of isoproterenol (ISO, 1.2 mg·kg-1·d-1) for a week. At the end of the experiment, the rats underwent echocardiography, followed by euthanasia and heart collection. We found that JMJD6 levels were compensatorily increased in ISO-induced hypertrophic cardiac tissues, but reduced in patients with heart failure with reduced ejection fraction (HFrEF). Furthermore, we demonstrated that JMJD6 overexpression significantly attenuated ISO-induced hypertrophy in neonatal rat cardiomyocytes (NRCMs) evidenced by the decreased cardiomyocyte surface area and hypertrophic genes expression. Cardiac-specific JMJD6 overexpression in rats protected the hearts against ISO-induced cardiac hypertrophy and fibrosis, and rescued cardiac function. Conversely, depletion of JMJD6 by single-guide RNA (sgRNA) exacerbated ISO-induced hypertrophic responses in NRCMs. We revealed that JMJD6 interacted with NF-κB p65 in cytoplasm and reduced nuclear levels of p65 under hypertrophic stimulation in vivo and in vitro. Mechanistically, JMJD6 bound to p65 and demethylated p65 at the R149 residue to inhibit the nuclear translocation of p65, thus inactivating NF-κB signaling and protecting against pathological cardiac hypertrophy. In addition, we found that JMJD6 demethylated histone H3R8, which might be a new histone substrate of JMJD6. These results suggest that JMJD6 may be a potential target for therapeutic interventions in cardiac hypertrophy and heart failure.

Cytoprotective, Cytotoxic and Cytostatic Roles of Autophagy in Response to BET Inhibitors

The bromodomain and extra-terminal domain (BET) family inhibitors are small molecules that target the dysregulated epigenetic readers, BRD2, BRD3, BRD4 and BRDT, at various transcription-related sites, including super-enhancers. BET inhibitors are currently under investigation both in pre-clinical cell culture and tumor-bearing animal models, as well as in clinical trials. However, as is the case with other chemotherapeutic modalities, the development of resistance is likely to constrain the therapeutic benefits of this strategy. One tumor cell survival mechanism that has been studied for decades is autophagy. Although four different functions of autophagy have been identified in the literature (cytoprotective, cytotoxic, cytostatic and non-protective), primarily the cytoprotective and cytotoxic forms appear to function in different experimental models exposed to BET inhibitors (with some evidence for the cytostatic form). This review provides an overview of the cytoprotective, cytotoxic and cytostatic functions of autophagy in response to BET inhibitors in various tumor models. Our aim is to determine whether autophagy targeting or modulation could represent an effective therapeutic strategy to enhance the response to these modalities and also potentially overcome resistance to BET inhibition.

Super-enhancer-driven lncRNA Snhg7 aggravates cardiac hypertrophy via Tbx5/GLS2/ferroptosis axis

Long non-coding RNAs (lncRNAs) are expressed aberrantly in cardiac disease, but their roles in cardiac hypertrophy are still unknown. Here we sought to identify a specific lncRNA and explore the mechanisms underlying lncRNA functions. Our results revealed that lncRNA Snhg7 was a super-enhancer-driven gene in cardiac hypertrophy by using chromatin immunoprecipitation sequencing (ChIP-Seq). We next found that lncRNA Snhg7 induced ferroptosis by interacting with T-box transcription factor 5 (Tbx5), a cardiac transcription factor. Moreover, Tbx5 bound to the promoter of glutaminase 2 (GLS2) and regulated cardiomyocyte ferroptosis activity in cardiac hypertrophy. Importantly, extra-terminal domain inhibitor JQ1 could suppress super-enhancers in cardiac hypertrophy. Inhibition of lncRNA Snhg7 could block the expressions of Tbx5, GLS2 and levels of ferroptosis in cardiomyocytes. Furthermore, we verified that Nkx2-5 as a core transcription factor, directly bound the super-enhancer of itself and lncRNA Snhg7, increasing both of their activation. Collectively, we are the first to identify lncRNA Snhg7 as a novel functional lncRNA in cardiac hypertrophy, might regulate cardiac hypertrophy via ferroptosis. Mechanistically, lncRNA Snhg7 could transcriptionally regulate Tbx5/GLS2/ferroptosis in cardiomyocytes.

Dual-target inhibitors of PARP1 in cancer therapy: a drug discovery perspective

Poly (ADP-ribose) polymerase 1 (PARP1), a key enzyme in DNA repair, has emerged as a promising anticancer druggable target. An increasing number of PARP1 inhibitors have been discovered to treat cancer, most notably those characterized by BRCA1/2 mutations. Although PARP1 inhibitors have achieved great clinical success, their cytotoxicity, development of drug resistance, and restriction of indication have weakened their clinical therapeutic effects. To address these issues, dual PARP1 inhibitors have been documented as a promising strategy. Here, we review recent progress in the development of dual PARP1 inhibitors, summarize the different designs of dual-target inhibitors, and introduce their antitumor pharmacology, shedding light on the discovery of dual PARP1 inhibitors for cancer treatment.

Jiedu Quyu Decoction mitigates monocrotaline-induced right-sided heart failure associated with pulmonary artery hypertension by inhibiting NLRP3 inflammasome in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Right-side heart failure could accelerate mortality in patients of pulmonary hypertension, Jiedu Quyu Decoction (JDQYF) was used to manage pulmonary hypertension, but its right-sided heart protective effect associated with pulmonary artery hypertension is still unclear.

AIM OF THE STUDY

Here, we evaluated the therapeutic effect of JDQYF on monocrotaline-induced right-sided heart failure associated with pulmonary arterial hypertension in Sprague-Dawley (SD) rats and investigated the potential mechanism of action.

MATERIALS AND METHODS

The main chemical components of JDQYF were detected and analyzed using ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry. The effects of JDQYF were investigated using a rat model of monocrotaline-induced right-sided heart failure associated with pulmonary arterial hypertension. We assessed the morphology of cardiac tissue using histopathology and the structure and function of the right heart using echocardiography. The biomarkers of heart failure, atrial natriuretic peptide and B-type natriuretic peptide, as well as serum pro-inflammatory markers, interleukin (IL)-1β, and IL-18, were measured by enzyme-linked immunosorbent assay (ELISA). Furthermore, the mRNA and protein expression levels of NLRP3 (NOD-, LRR-, and pyrin domain-containing 3), capase-1, IL-1β, and IL-18 in the right heart tissue were examined by real-time quantitative reverse transcription PCR and western blotting.

RESULTS

JDQYF improved ventricular function, alleviated pathological lesions in the right cardiac tissue, reduced the expression levels of biomarkers of heart failure and serum pro-inflammatory factors (IL-1β and IL-18), and downregulated the mRNA and protein expression levels of NLRP3, caspase-1, IL-1β, and IL-18 in the right cardiac tissue.

CONCLUSIONS

JDQYF possesses cardioprotective effect against right heart failure induced by pulmonary arterial hypertension, possibly owing to reduction of cardiac inflammation through the inhibition of NLRP3 inflammasome activation.

Apolipoprotein M Attenuates Anthracycline Cardiotoxicity and Lysosomal Injury

Apolipoprotein M (ApoM) binds sphingosine-1-phosphate (S1P) and is inversely associated with mortality in human heart failure (HF). Here, we show that anthracyclines such as doxorubicin (Dox) reduce circulating ApoM in mice and humans, that ApoM is inversely associated with mortality in patients with anthracycline-induced heart failure, and ApoM heterozygosity in mice increases Dox-induced mortality. In the setting of Dox stress, our studies suggest ApoM can help sustain myocardial autophagic flux in a post-transcriptional manner, attenuate Dox cardiotoxicity, and prevent lysosomal injury.

Isoginkgetin, a bioactive constituent from Ginkgo Biloba, protects against obesity-induced cardiomyopathy via enhancing Nrf2/ARE signaling

Obesity-induced metabolic cardiomyopathy (MC), characterized by lipotoxicity and excessive oxidative stress, emerges as the leading cause of heart failure in the obese patients. Yet, its therapy remains very limited. Here, we demonstrated that isoginkgetin (IGK), a bioactive biflavonoid isolated from medicinal herb Ginkgo Biloba, protected against obesity-induced cardiac diastolic dysfunction and adverse remodeling. Transcriptomics profiling revealed that IGK activated Nrf2 signaling in the heart tissues of the obese mice. Consistent with this observation, IGK treatment increased the nuclear translocation of Nrf2, which in turn trigger the activation of its downstream target genes (e. g. HO-1 and NQO1). In addition, IGK significantly rejuvenated mitochondrial defects in obese heart tissues as evidenced by enhancing mitochondrial respiratory capacity and resisting the collapse of mitochondrial potential and oxidative stress both in vitro and in vivo. Mechanistically, IGK stabilized Nrf2 protein via inhibiting the proteasomal degradation, independent of transcription regulation. Moreover, molecular docking and dynamics simulation assessment demonstrated a good binding mode between IGK and Nrf2/Keap1. Of note, the protective effects conferred by IGK against obesity-induced mitochondrial defects and cardiac dysfunction was compromised by Nrf2 gene silencing both in vitro and in vivo, consolidating a pivotal role of Nrf2 in IGK-elicited myocardial protection against MC. Thus, the present study identifies IGK as a promising drug candidate to alleviate obesity-induced oxidative stress and cardiomyocyte damage through Nrf2 activation, highlighting the therapeutic potential of IGK in ameliorating obesity-induced cardiomyopathy.

Super-enhancer-controlled positive feedback loop BRD4/ERα-RET-ERα promotes ERα-positive breast cancer

Estrogen and estrogen receptor alpha (ERα)-induced gene transcription is tightly associated with ERα-positive breast carcinogenesis. ERα-occupied enhancers, particularly super-enhancers, have been suggested to play a vital role in regulating such transcriptional events. However, the landscape of ERα-occupied super-enhancers (ERSEs) as well as key ERα-induced target genes associated with ERSEs remain to be fully characterized. Here, we defined the landscape of ERSEs in ERα-positive breast cancer cell lines, and demonstrated that bromodomain protein BRD4 is a master regulator of the transcriptional activation of ERSEs and cognate ERα target genes. RET, a member of the tyrosine protein kinase family of proteins, was identified to be a key ERα target gene of BRD4-regulated ERSEs, which, in turn, is vital for ERα-induced gene transcriptional activation and malignant phenotypes through activating the RAS/RAF/MEK2/ERK/p90RSK/ERα phosphorylation cascade. Combination therapy with BRD4 and RET inhibitors exhibited additive effects on suppressing ERα-positive breast cancer both in vitro and in vivo, comparable with that of standard endocrine therapy tamoxifen. Furthermore, combination therapy re-sensitized a tamoxifen-resistant ERα-positive breast cancer cell line to tamoxifen treatment. Taken together, our data uncovered the critical role of a super-enhancer-associated positive feedback loop constituting BRD4/ERα–RET–ERα in ERα-positive breast cancer, and suggested that targeting components in this loop would provide a new therapeutic avenue for treating ERα-positive breast cancer in the clinic.

Epigenetic Reader Bromodomain Containing Protein 2 Facilitates Pathological Cardiac Hypertrophy via Regulating the Expression of Citrate Cycle Genes

The bromodomain and extra-terminal domain proteins (BETs) family serve as epigenetic “readers”, which recognize the acetylated histones and recruit transcriptional regulator complexes to chromatin, eventually regulating gene transcription. Accumulating evidences demonstrate that pan BET inhibitors (BETi) confer protection against pathological cardiac hypertrophy, a precursor progress for developing heart failure. However, the roles of BET family members, except BRD4, remain unknown in pathological cardiac hypertrophy. The present study identified BRD2 as a novel regulator in cardiac hypertrophy, with a distinct mechanism from BRD4. BRD2 expression was elevated in cardiac hypertrophy induced by β-adrenergic agonist isoprenaline (ISO) in vivo and in vitro. Overexpression of BRD2 upregulated the expression of hypertrophic biomarkers and increased cell surface area, whereas BRD2 knockdown restrained ISO-induced cardiomyocyte hypertrophy. In vivo, rats received intramyocardial injection of adeno-associated virus (AAV) encoding siBRD2 significantly reversed ISO-induced pathological cardiac hypertrophy, cardiac fibrosis, and cardiac function dysregulation. The bioinformatic analysis of whole-genome sequence data demonstrated that a majority of metabolic genes, in particular those involved in TCA cycle, were under regulation by BRD2. Real-time PCR results confirmed that the expressions of TCA cycle genes were upregulated by BRD2, but were downregulated by BRD2 silencing in ISO-treated cardiomyocytes. Results of mitochondrial oxygen consumption rate (OCR) and ATP production measurement demonstrated that BRD2 augmented cardiac metabolism during cardiac hypertrophy. In conclusion, the present study revealed that BRD2 could facilitate cardiac hypertrophy through upregulating TCA cycle genes. Strategies targeting inhibition of BRD2 might suggest therapeutic potential for pathological cardiac hypertrophy and heart failure.

Tripartite motif 27 promotes cardiac hypertrophy via PTEN/Akt/mTOR signal pathways

Tripartite motif-containing 27 (Trim27) is highly expressed in tumor cells and regulates natural immunity and apoptosis. However, the effects of Trim27 in cardiac hypertrophy are not fully elucidated. In this study, we tried to explore the potential role of Trim27 in pressure overload-induced cardiac hypertrophy and the underlying mechanism. The results indicated that compared to sham operation (Sham) group, transverse aortic constriction (TAC) group showed significantly up-regulated Trim27 protein expression (P < 0.05). The neonatal rat cardiomyocytes (NRCMs) were isolated and stimulated with PBS, angiotensin (AngII) and phenylephrine (PE). NRCMs were collected to detect the protein expression of Trim27. The results were consistent with the results in vivo. Compared to PBS treatment, the expression of Trim27 protein in NRCMs was significantly increased after PE or AngII stimulation (P < 0.05, respectively). Knockout of Trim27 can reduce the size of cardiomyocytes and reduce the proteins expression of ANP, BNP, and β-MHC, improve cardiac function, and reverse myocardial hypertrophy (P < 0.05). Trim27 may be involved in regulating the development of cardiac hypertrophy. Further results showed that Trim27 can increase the protein expression of phosphorylation of Akt, GSK3β, mTOR, and P70s6k by interacting with PTEN (phosphatase tensin homolog). These findings revealed that Trim27 can promote cardiac hypertrophy by activating PTEN/Akt/GSK3β/mTOR signaling pathway.

microRNA-135a-5p regulates NOD-like receptor family pyrin domain containing 3 inflammasome-mediated hypertensive cardiac inflammation and fibrosis via thioredoxin-interacting protein

Hypertension is a severe public health problem that induces cardiac injury with alterations of gene expressions. The current study sought to evaluate the mechanism of microRNA(miR)-135a-5p in NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-mediation of cardiac inflammation and hypertensive cardiac fibrosis. Firstly, hypertensive mouse models were established using angiotensin II (Ang II), followed by miR-135a-5p agomir treatment. Subsequently, mouse blood pressure and basic cardiac function indexes, histopathological changes, and cardiac fibrosis were all determined, in addition to detection of factors related to inflammation and fibrosis. Additionally, mice cardiac fibroblasts (CFs) were isolated and treated with Ang II. The binding relationship of miR-135a-5p and thioredoxin-interacting protein (TXNIP) was predicted and testified, while the interaction of TXNIP and NLRP3 was detected by means of a co-immunoprecipitation assay. It was found that miR-135a-5p was poorly-expressed in Ang II-treated mice and further exerted cardioprotective effects against hypertensive heart diseases. Moreover, over-expression of miR-135a-5p resulted in inhibition of inflammatory infiltration and almost eliminated cardiac fibrosis, as evidenced by decreased Collagen (COL)-I, COL-III, a-smooth muscle actin, NLRP3, tumor necrosis factor-α, and interleukin-6. Mechanically, miR-135a-5p inhibited TXNIP expression to block the binding of TXNIP and NLRP3. On the other hand, TXNIP up-regulation reversed the protective role of miR-135a-5p over-expression in CFs. Collectively, our findings indicated that miR-135a-5p over-expression inhibited TXNIP expression to block the binding of TXNIP and NLRP3, thereby alleviating hypertensive cardiac inflammation and fibrosis.