Gelsolin (GSN) induces cardiomyocyte hypertrophy and BNP expression via p38 signaling and GATA-4 transcriptional factor activation

Actin-Binding Proteins in Cardiac Hypertrophy

The heart reacts to a large number of pathological stimuli through cardiac hypertrophy, which finally can lead to heart failure. However, the molecular mechanisms of cardiac hypertrophy remain elusive. Actin participates in the formation of highly differentiated myofibrils under the regulation of actin-binding proteins (ABPs), which provides a structural basis for the contractile function and morphological change in cardiomyocytes. Previous studies have shown that the functional abnormality of ABPs can contribute to cardiac hypertrophy. Here, we review the function of various actin-binding proteins associated with the development of cardiac hypertrophy, which provides more references for the prevention and treatment of cardiomyopathy.

Gelsolin Can Be a Prognostic Biomarker and Correlated with Immune Infiltrates in Gastric Cancer

BACKGROUND

Gelsolin (GSN) is the most widely expressed actin-severing protein in humans, which could regulate cell morphology, differentiation, movement and apoptosis. This study aims to explore the GSN as a prognostic biomarker of stomach adenocarcinoma (STAD).

METHODS

In this study, we used several online databases to comprehensively analyze the role of GSN in STAD. Oncomine and HPA databases were used to explore the GSN expression in various cancer, especially in gastric cancer. Then, UALCAN database was used to evaluate the relationship between GSN expression and promoter methylation in clinical characteristics. Finally, we used TIMER to analyze the correlation between GSN expression and immune infiltrates in gastric cancer.

RESULTS

GSN was down-regulated in gastric cancer, and decreased expression of GSN was related to worse survival. The GSN expression was significantly related to tumor purity in STAD and significantly correlated with infiltrating level of various immune cells, especially the dendritic cells.

CONCLUSION

Our study proposes that GSN can be served as the biomarker of disease and neoantigen for STAD treatment, which can improve the deficiency of disease-specific targeted therapies currently exist.

Oral administration of alcalase potato protein hydrolysate-APPH attenuates high fat diet-induced cardiac complications via TGF-β/GSN axis in aging rats

Consumption of high fat diet (HFD) is associated with increased cardiovascular risk factors among elderly people. Aging and obesity induced-cardiac remodeling includes hypertrophy and fibrosis. Gelsolin (GSN) induces cardiac hypertrophy and TGF-β, a key cytokine, which induces fibrosis. The relationship between TGF-β and GSN in aging induced cardiac remodeling is still unknown. We evaluated the expressions of TGF-β and GSN in HFD fed 22 months old aging SD rats, followed by the administration of either probucol or alcalase potato protein hydrolysate (APPH). Western blotting and Masson trichrome staining showed that APPH (45 and 75 mg/kg/day) and probucol (500 mg/kg/day) treatments significantly reduced the aging and HFD-induced hypertrophy and fibrosis. Echocardiograph showed that the performance of the hearts was improved in APPH, and probucol treated HFD aging rats. Serum from all rats was collected and H9c2 cells were cultured with collected serums separately. The GSN dependent hypertrophy was inhibited with an exogenous TGF-β in H9c2 cells cultured in HFD+ APPH treated serum. Thus, we propose that along with its role in cardiac fibrosis, TGF-β also acts as an upstream activator of GSN dependent hypertrophy. Hence, TGF-β in serum could be a promising therapeutic target for cardiac remodeling in aging and/or obese subjects.

Caspase Cleavage of Gelsolin Is an Inductive Cue for Pathologic Cardiac Hypertrophy

Background

Cardiac hypertrophy is an adaptive remodeling event that may improve or diminish contractile performance of the heart. Physiologic and pathologic hypertrophy yield distinct outcomes, yet both are dependent on caspase‐directed proteolysis. This suggests that each form of myocardial growth may derive from a specific caspase cleavage event(s). We examined whether caspase 3 cleavage of the actin capping/severing protein gelsolin is essential for the development of pathologic hypertrophy.

Methods and Results

Caspase targeting of gelsolin was established through protein analysis of hypertrophic cardiomyocytes and mass spectrometry mapping of cleavage sites. Pathologic agonists induced late‐stage caspase‐mediated cleavage of gelsolin. The requirement of caspase‐mediated gelsolin cleavage for hypertrophy induction was evaluated in primary cardiomyocytes by cell size analysis, monitoring of prohypertrophy markers, and measurement of hypertrophy‐related transcription activity. The in vivo impact of caspase‐mediated cleavage was investigated by echo‐guided intramyocardial injection of adenoviral‐expressed gelsolin. Expression of the N‐terminal gelsolin caspase cleavage fragment was necessary and sufficient to cause pathologic remodeling in isolated cardiomyocytes and the intact heart, whereas expression of a noncleavable form prevents cardiac remodeling. Alterations in myocardium structure and function were determined by echocardiography and end‐stage cardiomyocyte cell size analysis. Gelsolin secretion was also monitored for its impact on naïve cells using competitive antibody trapping, demonstrating that hypertrophic agonist stimulation of cardiomyocytes leads to gelsolin secretion, which induces hypertrophy in naïve cells.

Conclusions

These results suggest that cell autonomous caspase cleavage of gelsolin is essential for pathologic hypertrophy and that cardiomyocyte secretion of gelsolin may accelerate this negative remodeling response.

Interplay of N acetyl cysteine and melatonin in regulating oxidative stress-induced cardiac hypertrophic factors and microRNAs

Early and specific diagnosis of oxidative stress linked diseases as cardiac heart diseases remains a major dilemma for researchers and clinicians. MicroRNAs may serve as a better tool for specific early diagnostics and propose their utilization in future molecular medicines. We aimed to measure the microRNAs expressions in oxidative stress linked cardiac hypertrophic condition induced through stimulants as Endothelin and Isoproterenol. Cardiac hypertrophic animal models were confirmed by BNP, GATA4 expression, histological assays, and increased cell surface area. High oxidative stress (ROS level) and decreased antioxidant activities were assessed in hypertrophied groups. Enhanced expression of miR-152, miR-212/132 while decreased miR-142-3p expression was observed in hypertrophic condition. Similar pattern of these microRNAs was detected in HL-1 cells treated with H₂O₂. Upon administration of antioxidants, the miRNAs expression pattern altered from that of the cardiac hypertrophied model. Present investigation suggests that oxidative stress generated during the cardiac pathology may directly or indirectly regulate anti-hypertrophy pathway elements through microRNAs including antioxidant enzymes, which need further investigation. The down-regulation of free radical scavengers make it easier for the oxidative stress to play a key role in disease progression.

MiR-21 protected against diabetic cardiomyopathy induced diastolic dysfunction by targeting gelsolin

Background

Diabetes is a leading cause of mortality and morbidity across the world. Over 50% of deaths among diabetic patients are caused by cardiovascular diseases. Cardiac diastolic dysfunction is one of the key early signs of diabetic cardiomyopathy, which often occurs before systolic dysfunction. However, no drug is currently licensed for its treatment.

Methods

Type 9 adeno-associated virus combined with cardiac Troponin T promoter were employed to manipulate miR-21 expression in the leptin receptor-deficient (db/db) mice. Cardiac structure and functions were measured by echocardiography and hemodynamic examinations. Primary cardiomyocytes and cardiomyocyte cell lines were used to perform gain/loss-of-function assays in vitro.

Results

We observed a significant reduction of miR-21 in the diastolic dysfunctional heart of db/db mice. Remarkably, delivery of miR-21 efficiently protected against the early impairment in cardiac diastolic dysfunction, represented by decreased ROS production, increased bioavailable NO and relieved diabetes-induced cardiomyocyte hypertrophy in db/db mice. Through bioinformatic analysis and Ago2 co-immunoprecipitation, we identified that miR-21 directly targeted gelsolin, a member of the actin-binding proteins, which acted as a transcriptional cofactor in signal transduction. Moreover, down-regulation of gelsolin by siRNA also attenuated the early phase of diabetic cardiomyopathy.

Conclusion

Our findings reveal a new role of miR-21 in attenuating diabetic cardiomyopathy by targeting gelsolin, and provide a molecular basis for developing a miRNA-based therapy against diabetic cardiomyopathy.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0767-z) contains supplementary material, which is available to authorized users.

Oolong tea prevents cardiomyocyte loss against hypoxia by attenuating p-JNK mediated hypertrophy and enhancing P-IGF1R, p-akt, and p-Badser136 activity and by fortifying NRF2 antioxidation system

Tea, the most widely consumed natural beverage has been associated with reduced mortality risk from cardiovascular disease. Oolong tea is a partially fermented tea containing high levels of catechins, their degree of oxidation varies between 20%-80% causing differences in their active metabolites. In this study we examined the effect of oolong tea extract (OTE) obtained by oxidation at low-temperature for short-time against hypoxic injury and found that oolong tea provides cyto-protective effects by suppressing the JNK mediated hypertrophic effects and by enhancing the innate antioxidant mechanisms in neonatal cardiomyocytes and in H9c2 cells. OTE effectively attenuates 24 h hypoxia-triggered cardiomyocyte loss by suppressing caspase-3-cleavage and apoptosis in a dose-dependent manner. OTE also enhances the IGFIR/p-Akt associated survival-mechanism involving the elevation of p-Bad^ser136 in a dose-dependent manner to aid cellular adaptations against hypoxic challenge. The results show the effects and mechanism of Oolong tea to provide cardio-protective benefits during hypoxic conditions.

Gelsolin-mediated activation of PI3K/Akt pathway is crucial for hepatocyte growth factor-induced cell scattering in gastric carcinoma

In gastric cancer (GC), the main subtypes (diffuse and intestinal types) differ in pathological characteristics, with diffuse GC exhibiting early disseminative and invasive behaviour. A distinctive feature of diffuse GC is loss of intercellular adhesion. Although widely attributed to mutations in the CDH1 gene encoding E-cadherin, a significant percentage of diffuse GC do not harbor CDH1 mutations. We found that the expression of the actin-modulating cytoskeletal protein, gelsolin, is significantly higher in diffuse-type compared to intestinal-type GCs, using immunohistochemical and microarray analysis. Furthermore, in GCs with wild-type CDH1, gelsolin expression correlated inversely with CDH1 gene expression. Downregulating gelsolin using siRNA in GC cells enhanced intercellular adhesion and E-cadherin expression, and reduced invasive capacity. Interestingly, hepatocyte growth factor (HGF) induced increased gelsolin expression, and gelsolin was essential for HGF-medicated cell scattering and E-cadherin transcriptional repression through Snail, Twist and Zeb2. The HGF-dependent effect on E-cadherin was found to be mediated by interactions between gelsolin and PI3K-Akt signaling. This study reveals for the first time a function of gelsolin in the HGF/cMet oncogenic pathway, which leads to E-cadherin repression and cell scattering in gastric cancer. Our study highlights gelsolin as an important pro-disseminative factor contributing to the aggressive phenotype of diffuse GC.

GATA4 regulates osteoblastic differentiation and bone remodeling via p38-mediated signaling

Osteoblasts play a major role in bone remodeling and are regulated by transcription factors. GATA4, a zinc finger transcription factor from the GATA family, has an unclear role in osteoblast differentiation. In this study, the role of GATA4 in osteoblast differentiation was studied both in vitro and in vivo by GATA4 knockdown. GATA4 expression increased during osteoblast differentiation. GATA4 knockdown in osteoblast precursor cells reduced alkaline phosphatase activity and decreased the formation of calcified nodule in an osteogenic-induced cell culture system. In vivo, micro-CT showed that local injection of lentivirus-delivered GATA4 shRNA caused reduced new bone formation during tooth movement. Histological analyses such as total collagen and Goldner's trichrome staining confirmed these results. In vivo immunohistochemical analysis showed reduced expression of osterix (OSX), osteopontin (OPN), and osteocalcin (OCN) in the shGATA4 group (P < 0.05). Consistently, both western blotting and quantitative reverse-transcription PCR proved that expression of osteogenesis-related genes, including OSX, OPN, and OCN, was significantly repressed in the shGATA4 group in vitro (P < 0.01). For further analysis of the pathways involved in this process, we examined the MAPK signaling pathway, and found knockdown of GATA4, downregulated p38 signaling pathways (P < 0.01). Collectively, these results imply GATA4 is a regulator of osteoblastic differentiation via the p38 signaling pathways.

The Role of p38 MAPK in the Development of Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) is a major complication of diabetes that contributes to an increase in mortality. A number of mechanisms potentially explain the development of DCM including oxidative stress, inflammation and extracellular fibrosis. Mitogen-activated protein kinase (MAPK)-mediated signaling pathways are common among these pathogenic responses. Among the diverse array of kinases, extensive attention has been given to p38 MAPK due to its capacity for promoting or inhibiting the translation of target genes. Growing evidence has indicated that p38 MAPK is aberrantly expressed in the cardiovascular system, including the heart, under both experimental and clinical diabetic conditions and, furthermore, inhibition of p38 MAPK activation in transgenic animal model or with its pharmacologic inhibitor significantly prevents the development of DCM, implicating p38 MAPK as a novel diagnostic indicator and therapeutic target for DCM. This review summarizes our current knowledge base to provide an overview of the impact of p38 MAPK signaling in diabetes-induced cardiac remodeling and dysfunction.

Zinc deficiency exacerbates while zinc supplement attenuates cardiac hypertrophy in high-fat diet-induced obese mice through modulating p38 MAPK-dependent signaling

Childhood obesity often leads to cardiovascular diseases, such as obesity-related cardiac hypertrophy (ORCH), in adulthood, due to chronic cardiac inflammation. Zinc is structurally and functionally essential for many transcription factors; however, its role in ORCH and underlying mechanism(s) remain unclear and were explored here in mice with obesity induced with high-fat diet (HFD). Four week old mice were fed on either HFD (60%kcal fat) or normal diet (ND, 10% kcal fat) for 3 or 6 months, respectively. Either diet contained one of three different zinc quantities: deficiency (ZD, 10mg zinc per 4057kcal), normal (ZN, 30mg zinc per 4057kcal) or supplement (ZS, 90mg zinc per 4057kcal). HFD induced a time-dependent obesity and ORCH, which was accompanied by increased cardiac inflammation and p38 MAPK activation. These effects were worsened by ZD in HFD/ZD mice and attenuated by ZS in HFD/ZS group, respectively. Also, administration of a p38 MAPK specific inhibitor in HFD mice for 3 months did not affect HFD-induced obesity, but completely abolished HFD-induced, and zinc deficiency-worsened, ORCH and cardiac inflammation. In vitro exposure of adult cardiomyocytes to palmitate induced cell hypertrophy accompanied by increased p38 MAPK activation, which was heightened by zinc depletion with its chelator TPEN. Inhibition of p38 MAPK with its specific siRNA also prevented the effects of palmitate on cardiomyocytes. These findings demonstrate that ZS alleviates but ZD heightens cardiac hypertrophy in HFD-induced obese mice through suppressing p38 MAPK-dependent cardiac inflammatory and hypertrophic pathways.

Quantitative proteomic analysis of serum from pregnant women carrying a fetus with conotruncal heart defect using isobaric tags for relative and absolute quantitation (iTRAQ) labeling

Objective

To identify differentially expressed proteins from serum of pregnant women carrying a conotruncal heart defects (CTD) fetus, using proteomic analysis.

Methods

The study was conducted using a nested case-control design. The 5473 maternal serum samples were collected at 14–18 weeks of gestation. The serum from 9 pregnant women carrying a CTD fetus, 10 with another CHD (ACHD) fetus, and 11 with a normal fetus were selected from the above samples, and analyzed by using isobaric tags for relative and absolute quantitation (iTRAQ) coupled with two-dimensional liquid chromatography-tandem mass spectrometry(2D LC-MS/MS). The differentially expressed proteins identified by iTRAQ were further validated with Western blot.

Results

A total of 105 unique proteins present in the three groups were identified, and relative expression data were obtained for 92 of them with high confidence by employing the iTRAQ-based experiments. The downregulation of gelsolin in maternal serum of fetus with CTD was further verified by Western blot.

Conclusions

The identification of differentially expressed protein gelsolin in the serum of the pregnant women carrying a CTD fetus by using proteomic technology may be able to serve as a foundation to further explore the biomarker for detection of CTD fetus from the maternal serum.