Subcellular Localization of Survivin Determines Its Function in Cardiomyocytes

Identification of immune-related genes and small-molecule drugs in hypertension-induced left ventricular hypertrophy based on machine learning algorithms and molecular docking

Background

Left ventricular hypertrophy (LVH) is a common consequence of hypertension and can lead to heart failure. The immune response plays an important role in hypertensive LVH; however, there is no comprehensive method to investigate the mechanistic relationships between immune response and hypertensive LVH or to find novel therapeutic targets. This study aimed to screen hub immune-related genes involved in hypertensive LVH as well as to explore immune target-based therapeutic drugs.

Materials and methods

RNA-sequencing data from a mouse model generated by angiotensin II infusion were subjected to weighted gene co-expression network analysis (WGCNA) to identify core expression modules. Machine learning algorithms were applied to screen immune-related LVH characteristic genes. Heart structures were evaluated by echocardiography and cardiac magnetic resonance imaging (CMRI). Validation of hub genes was conducted by RT-qPCR and western blot. Using the Connectivity Map database and molecular docking, potential small-molecule drugs were explored.

Results

A total of 1215 differentially expressed genes were obtained, most of which were significantly enriched in immunoregulation and collagen synthesis. WGCNA and multiple machine learning strategies uncovered six hub immune-related genes (Ankrd1, Birc5, Nuf2, C1qtnf6, Fcgr3, and Cdca3) that may accurately predict hypertensive LVH diagnosis. Immune analysis revealed that fibroblasts and macrophages were closely correlated with hypertensive LVH, and hub gene expression was significantly associated with these immune cells. A regulatory network of transcription factor-mRNA and a ceRNA network of miRNA-lncRNA was established. Notably, six hub immune-related genes were significantly increased in the hypertensive LVH model, which were positively linked to left ventricle wall thickness. Finally, 12 small-molecule compounds with the potential to reverse the high expression of hub genes were ruled out as potential therapeutic agents for hypertensive LVH.

Conclusion

This study identified and validated six hub immune-related genes that may play essential roles in hypertensive LVH, providing new insights into the potential pathogenesis of cardiac remodeling and novel targets for medical interventions.

Development and validation of Ran as a prognostic marker in stage I and stage II primary breast cancer

PURPOSE

Existing prognostic biomarkers are inadequate for stratifying breast cancer patients with the highest risk of tumor progression at the time of diagnosis. Here, we demonstrate that the small GTPase Ran has predictive value for breast cancer (BC) patients as a whole, and for specific BC subtypes.

PATIENTS AND METHODS

Ran expression was quantified by immunohistochemistry in 263 patients with primary breast cancer diagnosed at the Breast Unit, Royal Liverpool Hospital. Additionally as an independent validation, we also analyzed the mRNA expressions of Ran, ER, PR, and Cerb-2, the triple-negative endocrine receptors, and their associations with patient survival in a combined patient cohorts of multiple public datasets (n = 1079). We analyzed the data with Spearman's rank correlation and Kaplan-Meier plots coupled with Wilcoxon-Gehan tests, respectively. All statistical tests were two-sided.

RESULTS

Ran nuclear, cytoplasmic, and total staining are substantially associated with poor survival, independent of conventional prognostic markers such as estrogen receptor (ER), human epidermal growth factor receptor 2 (HER2), and lymph node status. According to the datasets, Ran was significantly correlated with distant metastasis-free survival (DMFS) and relapse-free survival (RFS).

CONCLUSION

We found that Ran expression is a unique predictive biomarker for patient survival, metastasis, and tumor relapse. This biomarker could be used for diagnostic purposes, using formalin-fixed, paraffin-embedded tumor biopsy samples from breast cancer patients in the early stages.

Overexpression of MRP1/ABCC1, Survivin and BCRP/ABCC2 Predicts the Resistance of Diffuse Large B-Cell Lymphoma to R-CHOP Treatment

BACKGROUND

Approximately 40% of patients with diffuse large B-cell lymphoma (DLBCL) experience treatment resistance to the first-line R-CHOP regimen. ATP binding cassette (ABC) transporters and survivin might play a role in multidrug resistance (MDR) in various tumors. The aim was to investigate if the coexpression of ABC transporters and survivin was associated with R-CHOP treatment response.

METHODS

The expression of Bcl-2, survivin, P-glycoprotein/ABCB1, MRP1/ABCC1, and BCRP/ABCC2 was analyzed using immunohistochemistry in tumor specimens obtained from patients with DLBCL, and classified according to the treatment response as Remission, Relapsed, and (primary) Refractory groups. All patients received R-CHOP or equivalent treatment.

RESULTS

Bcl-2 was in strong positive correlation with clinical parameters and all biomarkers except P-gp/ABCB1. The overexpression of MRP1/ABCC1, survivin, and BCRP/ABCC2 presented as high immunoreactive scores (IRSs) was detected in the Refractory and Relapsed groups (p < 0.05 vs. Remission), respectively, whereas the IRS of P-gp/ABCB1 was low. Significant correlations were found among either MRP1/ABCC1 and survivin or BCRP/ABCC2 in the Refractory and Relapsed groups, respectively. In multiple linear regression analysis, ECOG status along with MRP1/ABCC1 or survivin and BRCP/ABCG2 was significantly associated with the prediction of the R-CHOP treatment response.

CONCLUSIONS

DLBCL might harbor certain molecular signatures such as MRP1/ABCC1, survivin, and BCRP/ABCC2 overexpression that can predict resistance to R-CHOP.

Yellow mealworm (Tenebrio Molitor) enhances intestinal immunity in largemouth bass (Micropterus salmoides) via the NFκB/survivin signaling pathway

This study aimed to elucidate the mechanisms of yellow mealworm (Tenebrio Molitor, YM) in intestinal immunity and health. Largemouth bass, as an enteritis modeling animal, were fed 3 diets containing YM at 0% (YM0), 24% (YM24) and 48% (YM48). The YM24 group had reduced levels of proinflammatory cytokines, while the YM48 group experienced a negative impact on intestinal health. Next, the Edwardsiella tarda (E. tarda) challenge test consisted of 4 YM diets, 0% (EYM0), 12% (EYM12), 24% (EYM24), and 36% (EYM36). The EYM0 and EYM12 groups exhibited intestinal damage and immunosuppression by the pathogenic bacteria. However, the above adverse phenotypes were attenuated in the EYM24 and EYM36 groups. Mechanistically, the EYM24 and EYM36 groups enhanced intestinal immunity in largemouth bass via activating NFκBp65 and further upregulating survivin expression to inhibit apoptosis. The results identify a protective mechanism of YM as a novel food or feed source by improving intestinal health.

A nanobody-based molecular toolkit for ubiquitin-proteasome system explores the main role of survivin subcellular localization

Targeted protein degradation is a powerful tool for determining the function of specific proteins nowadays. Survivin is the smallest member of the inhibitor of the apoptosis protein (IAP) family. It exists in the cytoplasm and nucleus of cells, but the exact function of survivin in different subcellular locations retained unclear updates due to the lack of effective and simple technical means. In this study, we created a novel nanoantibody-based molecular toolkit, namely, the ubiquitin-proteasome system (Nb4A-Fc-T2A-TRIM21), that can target to degrade survivin localized in cytoplasmic and cell nuclear by ubiquitinating, and by which to verify the potential roles of survivin subcellular localization. Also, the results showed that the cytoplasmic survivin mainly plays an anti-apoptotic function by directly or indirectly inhibiting the caspase pathway, and the nuclear survivin mainly promotes cell proliferation and participates in the regulation of the cell cycle. In addition, the Nb4A-Fc-T2A-TRIM21 system can degrade the endogenous survivin protein in a large amount by the ubiquitin-proteasome pathway, and the system can provide theoretical support for ubiquitination degradation targeting other endogenous proteins.

Amelioration of Endotoxin-Induced Acute Lung Injury and Alveolar Epithelial Cells Apoptosis by Simvastatin Is Associated with Up-Regulation of Survivin/NF-kB/p65 Pathway

Disruption of the alveolar−endothelial barrier caused by inflammation leads to the progression of septic acute lung injury (ALI). In the present study, we investigated the beneficial effects of simvastatin on the endotoxin lipopolysaccharide (LPS)-induced ALI and its related mechanisms. A model of ALI was induced within experimental sepsis developed by intraperitoneal injection of a single non-lethal LPS dose after short-term simvastatin pretreatment (10−40 mg/kg orally). The severity of the lung tissue inflammatory injury was expressed as pulmonary damage scores (PDS). Alveolar epithelial cell apoptosis was confirmed by TUNEL assay (DNA fragmentation) and expressed as an apoptotic index (AI), and immunohistochemically for cleaved caspase-3, cytochrome C, and anti-apoptotic Bcl-xL, an inhibitor of apoptosis, survivin, and transcriptional factor, NF-kB/p65. Severe inflammatory injury of pulmonary parenchyma (PDS 3.33 ± 0.48) was developed after the LPS challenge, whereas simvastatin significantly and dose-dependently protected lung histology after LPS (p < 0.01). Simvastatin in a dose of 40 mg/kg showed the most significant effects in amelioration alveolar epithelial cells apoptosis, demonstrating this as a marked decrease of AI (p < 0.01 vs. LPS), cytochrome C, and cleaved caspase-3 expression. Furthermore, simvastatin significantly enhanced the expression of Bcl-xL and survivin. Finally, the expression of survivin and its regulator NF-kB/p65 in the alveolar epithelium was in strong positive correlation across the groups. Simvastatin could play a protective role against LPS-induced ALI and apoptosis of the alveolar−endothelial barrier. Taken together, these effects were seemingly mediated by inhibition of caspase 3 and cytochrome C, a finding that might be associated with the up-regulation of cell-survival survivin/NF-kB/p65 pathway and Bcl-xL.

Ablation of Survivin in T Cells Attenuates Acute Allograft Rejection after Murine Heterotopic Heart Transplantation by Inducing Apoptosis

Although studies in oncology have well explored the pharmacological effects of Birc5, little is known about its role in allogeneic T-cell responses. Therefore, the present study used a mouse model of acute heart allograft rejection to investigate the protective effect and mechanism of conditional knockout of Birc5 in T cells. Survivin (encoded by Birc5) was up-regulated in T cells activated in vivo and in vitro. Deletion of Birc5 in T cells attenuated acute heart allograft rejection by reducing the ratio of effector to naive T cells and Th1 to Tregs. In addition, deletion of Birc5 had no noticeable effect on proliferation but on apoptosis and the secretion of IFN-γ. The results revealed a significant increase in the percentage of Annexin V positive CD4⁺ T cells in the Birc5^-/- group, compared to the WT. Moreover, there was significant increase in early apoptotic alloreactive T cells in Birc5^-/- mice and this was partly mediated by caspase-3. Furthermore, treatment with YM155 inhibited acute heart allograft rejection in vivo and increased T-cell apoptosis in healthy human PBMCs in vitro. The results highlight a potential therapeutic target for the prevention and treatment of acute transplant rejection.

Silencing Survivin: a Key Therapeutic Strategy for Cardiac Hypertrophy

Cardiac hypertrophy, in its aspects of localized thickening of the interventricular septum and concentric increase of the left ventricle, constitutes a risk factor of heart failure. Myocardial hypertrophy, in the presence of different degree of myocardial fibrosis, is paralleled by significant molecular, cellular, and histological changes inducing alteration of cardiac extracellular matrix composition as well as sarcomeres and cytoskeleton remodeling. Previous studies indicate osteopontin (OPN) and more recently survivin (SURV) overexpression as the hallmarks of heart failure although SURV function in the heart is not completely clarified. In this study, we investigated the involvement of SURV in intracellular signaling of hypertrophic cardiomyocytes and the impact of its transcriptional silencing, laying the foundation for novel target gene therapy in cardiac hypertrophy. Oligonucleotide-based molecules, like theranostic optical nanosensors (molecular beacons) and siRNAs, targeting SURV and OPN mRNAs, were developed. Their diagnostic and therapeutic potential was evaluated in vitro in hypertrophic FGF23-induced human cardiomyocytes and in vivo in transverse aortic constriction hypertrophic mouse model. Engineered erythrocyte was used as shuttle to selectively target and transfer siRNA molecules into unhealthy cardiac cells in vivo. The results highlight how the SURV knockdown could negatively influence the expression of genes involved in myocardial fibrosis in vitro and restores structural, functional, and morphometric features in vivo. Together, these data suggested that SURV is a key factor in inducing cardiomyocytes hypertrophy, and its shutdown is crucial in slowing disease progression as well as reversing cardiac hypertrophy. In the perspective, targeted delivery of siRNAs through engineered erythrocytes can represent a promising therapeutic strategy to treat cardiac hypertrophy. Theranostic SURV molecular beacon (MB-SURV), transfected into FGF23-induced hypertrophic human cardiomyocytes, significantly dampened SURV overexpression. SURV down-regulation determines the tuning down of MMP9, TIMP1 and TIMP4 extracellular matrix remodeling factors while induces the overexpression of the cardioprotective MCAD factor, which counterbalance the absence of pro-survival and anti-apoptotic SURV activity to protect cardiomyocytes from death. In transverse aortic constriction (TAC) mouse model, the SURV silencing restores the LV mass levels to values not different from the sham group and counteracts the progressive decline of EF, maintaining its values always higher with respect to TAC group. These data demonstrate the central role of SURV in the cardiac reverse remodeling and its therapeutic potential to reverse cardiac hypertrophy.

Targeting 14-3-3ε activates apoptotic signaling to prevent cutaneous squamous cell carcinoma

More than a million cases of cutaneous squamous cell carcinoma are diagnosed in the USA each year, and its incidence is increasing. Most of these malignancies arise from premalignant lesions, providing an opportunity for intervention before malignant progression. We previously documented how cytoplasmic mislocalization of CDC25A in premalignant and malignant skin cancers confers resistance to apoptotic cell death via a mechanism that depends on its interaction with 14-3-3ε. From these data, we hypothesized that 14-3-3ε overexpression drives skin tumor development and progression, such that targeting 14-3-3ε may be a useful strategy for skin cancer treatment. Like CDC25A, 14-3-3ε was overexpressed and mislocalized to the cytoplasm of both benign and malignant human skin cancer. Skin-targeted deletion of the 14-3-3ε gene reduced skin tumor development by 75% and blocked malignant progression. 14-3-3ε suppressed apoptosis through activation of Akt, leading to inhibition of BCL2 associated agonist of cell death and upregulation of Survivin. Using virtual tetrapeptide libraries, we developed a novel peptide that specifically blocked 14-3-3ε heterodimerization and thereby prevented its interaction with CDC25A. The peptide reduced prosurvival signaling, killed skin cancer cells and reduced skin tumor growth in xenograft. Normal skin keratinocytes were unaffected by inhibition or deletion of 14-3-3ε. Thus, targeting of 14-3-3ε dimerization is a promising strategy for the treatment of premalignant skin lesions.

Protective Effects of Simvastatin on Endotoxin-Induced Acute Kidney Injury through Activation of Tubular Epithelial Cells' Survival and Hindering Cytochrome C-Mediated Apoptosis

Increasing evidence suggests that apoptosis of tubular cells and renal inflammation mainly determine the outcome of sepsis-associated acute kidney injury (AKI). The study aim was to investigate the molecular mechanism involved in the renoprotective effects of simvastatin in endotoxin (lipopolysaccharide, LSP)-induced AKI. A sepsis model was established by intraperitoneal injection of a single non-lethal LPS dose after short-term simvastatin pretreatment. The severity of the inflammatory injury was expressed as renal damage scores (RDS). Apoptosis of tubular cells was detected by Terminal deoxynucleotidyl transferase-mediated dUTP Nick End Labeling (TUNEL assay) (apoptotic DNA fragmentation, expressed as an apoptotic index, AI) and immunohistochemical staining for cleaved caspase-3, cytochrome C, and anti-apoptotic Bcl-xL and survivin. We found that endotoxin induced severe renal inflammatory injury (RDS = 3.58 ± 0.50), whereas simvastatin dose-dependently prevented structural changes induced by LPS. Furthermore, simvastatin 40 mg/kg most profoundly attenuated tubular apoptosis, determined as a decrease of cytochrome C, caspase-3 expression, and AIs (p  <  0.01 vs. LPS). Conversely, simvastatin induced a significant increase of Bcl-XL and survivin, both in the strong inverse correlations with cleaved caspase-3 and cytochrome C. Our study indicates that simvastatin has cytoprotective effects against LPS-induced tubular apoptosis, seemingly mediated by upregulation of cell-survival molecules, such as Bcl-XL and survivin, and inhibition of the mitochondrial cytochrome C and downstream caspase-3 activation.

Hypoxia-induced H19/YB-1 cascade modulates cardiac remodeling after infarction

Rationale: Long non-coding RNA (lncRNAs) has been identified as a pivotal novel regulators in cardiac development as well as cardiac pathogenesis. lncRNA H19 is known as a fetal gene but it is exclusively abundant in the heart and skeletal muscles in adulthood, and is evolutionarily conserved in humans and mice. It has been reported to possess a significant correlation with the risk of coronary artery diseases. However, the function of H19 is not well characterized in heart.

Methods: Loss-of-function and gain-of-function mouse models with left anterior descending coronary artery-ligation surgery were utilized to evaluate the functionality of H19 in vivo. For mechanistic studies, hypoxia condition were exerted in in vitro models to mimic cardiac ischemic injury. Chromatin isolation by RNA immunoprecipitation (ChIRP) was performed to reveal the interacting protein of lncRNA H19.

Results: lncRNA H19 was significantly upregulated in the infarct area post-surgery day 4 in mouse model. Ectopic expression of H19 in the mouse heart resulted in severe cardiac dilation and fibrosis. Several extracellular matrix (ECM) genes were significantly upregulated. While genetic ablation of H19 by CRISPR-Cas9 ameliorated post-MI cardiac remodeling with reduced expression in ECM genes. Through chromatin isolation by RNA purification (ChIRP), we identified Y-box-binding protein (YB)-1, a suppressor of Collagen 1A1, as an interacting protein of H19. Furthermore, H19 acted to antagonize YB-1 through direct interaction under hypoxia, which resulted in de-repression of Collagen 1A1 expression and cardiac fibrosis.

Conclusions: Together these results demonstrate that lncRNA H19 and its interacting protein YB-1 are crucial for ECM regulation during cardiac remodeling.

Survivin expression and localization in different organs of yaks (Bos grunniens)

Yaks (Bos grunniens) have special physiological structures that help them adapt to high-altitude environments. Survivin is actively studied in cancer tissues, but less in normal tissues. Therefore, the aim of the present study was to analysis the relationship between survivin expression and apoptosis rate in yaks. A partial gene sequence of survivin was cloned and characterized using bioinformatics. The expression of survivin was investigated using real-time quantitative PCR (RT-qPCR) and western blot (WB) analysis and localized using immunohistochemistry (IHC). The results revealed that in normal physiological organs, survivin is mainly expressed in cytoplasm and its expression was up-regulated with age. Its expression in heart and liver was higher than in other organs, such as spleen, lung, brain, kidney, and testis. It is noteworthy that the expression of survivin in spleen is differed from that in other organs. Therefore, we selected immune organs (lymph node, thymus and spleen) to investigate the relationship between survivin expression and apoptosis. Caspase-3 was used as a reference. Within the same age group, the expression of survivin was the highest in the spleen, but that of caspase-3 was the highest in the lymph node (P < 0.01). Furthermore, the IHC analysis revealed that survivin and caspase-3 are expressed in the same location (mainly in the cytoplasm, Hassall's corpuscles, the medulla of the lymph node, the red pulp and marginal zone of the spleen. More importantly, survivin expression was down-regulated with age in immune organs, and the opposite trend was observed for caspase-3 expression (P < 0.01). The results proved that the expression of survivin and caspase-3 is down- and up-regulated with age, respectively, suggesting that survivin and caspase-3 might coordinating and participating in slowing down the rate of apoptosis rate in immune organs of healthy yak.

Simvastatin Protects Cardiomyocytes Against Endotoxin-induced Apoptosis and Up-regulates Survivin/NF-κB/p65 Expression

This study is aimed to investigate whether simvastatin induces cardiomyocytes survival signaling in endotoxin (lipopolysaccharide, LSP)-induced myocardial injury, and if so, further to determine a role of survivin in simvastatin-anti-apoptotic effect. Wistar rats were pretreated with simvastatin (10–40 mg/kg po) before a single non-lethal dose of LPS. In myocardial tissue, LPS induced structural disorganization of myofibrils with significant inflammatory infiltrate (cardiac damage score, CDS = 3.87 ± 0.51, p < 0.05), whereas simvastatin dose-dependently abolished structural changes induced by LPS (p < 0.01). Simvastatin in 20 mg/kg and 40 mg/kg pretreatment, dose dependently, attenuated myocardial apoptosis determined as apoptotic index (28.8 ± 4.5% and 18.9 ± 3.5, p < 0.05), decreased cleaved caspase-3 expression (32.1 ± 5.8%, p < 0.01), along with significant Bcl-xL expression in the simvastatin groups (p < 0.01). Interestingly, in the simvastatin groups were determined significantly increased expression of survivin (p < 0.01), but in negative correlation with cleaved caspase-3 and apoptotic indices (p < 0.01). Simvastatin has a cardioprotective effects against LPS induced apoptosis. The effect may be mediated by up-regulation of survivin via activation of NF-κB, which leads to reduced activation of caspase-3 and consequent apoptosis of cardiomyocytes in experimental sepsis.