Bone morphogenic protein-4 induces endothelial cell apoptosis through oxidative stress-dependent p38MAPK and JNK pathway

Deficiency of neutral cholesterol ester hydrolase 1 (NCEH1) impairs endothelial function in diet-induced diabetic mice

BACKGROUND

Neutral cholesterol ester hydrolase 1 (NCEH1) plays a critical role in the regulation of cholesterol ester metabolism. Deficiency of NCHE1 accelerated atherosclerotic lesion formation in mice. Nonetheless, the role of NCEH1 in endothelial dysfunction associated with diabetes has not been explored. The present study sought to investigate whether NCEH1 improved endothelial function in diabetes, and the underlying mechanisms were explored.

METHODS

The expression and activity of NCEH1 were determined in obese mice with high-fat diet (HFD) feeding, high glucose (HG)-induced mouse aortae or primary endothelial cells (ECs). Endothelium-dependent relaxation (EDR) in aortae response to acetylcholine (Ach) was measured.

RESULTS

Results showed that the expression and activity of NCEH1 were lower in HFD-induced mouse aortae, HG-exposed mouse aortae ex vivo, and HG-incubated primary ECs. HG exposure reduced EDR in mouse aortae, which was exaggerated by endothelial-specific deficiency of NCEH1, whereas NCEH1 overexpression restored the impaired EDR. Similar results were observed in HFD mice. Mechanically, NCEH1 ameliorated the disrupted EDR by dissociating endothelial nitric oxide synthase (eNOS) from caveolin-1 (Cav-1), leading to eNOS activation and nitric oxide (NO) release. Moreover, interaction of NCEH1 with the E3 ubiquitin-protein ligase ZNRF1 led to the degradation of Cav-1 through the ubiquitination pathway. Silencing Cav-1 and upregulating ZNRF1 were sufficient to improve EDR of diabetic aortas, while overexpression of Cav-1 and downregulation of ZNRF1 abolished the effects of NCEH1 on endothelial function in diabetes. Thus, NCEH1 preserves endothelial function through increasing NO bioavailability secondary to the disruption of the Cav-1/eNOS complex in the endothelium of diabetic mice, depending on ZNRF1-induced ubiquitination of Cav-1.

CONCLUSIONS

NCEH1 may be a promising candidate for the prevention and treatment of vascular complications of diabetes.

Different PfEMP1-expressing Plasmodium falciparum variants induce divergent endothelial transcriptional responses during co-culture

The human malaria parasite Plasmodium falciparum is responsible for the majority of mortality and morbidity caused by malaria infection and differs from other human malaria species in the degree of accumulation of parasite-infected red blood cells in the microvasculature, known as cytoadherence or sequestration. In P. falciparum, cytoadherence is mediated by a protein called PfEMP1 which, due to its exposure to the host immune system, undergoes antigenic variation resulting in the expression of different PfEMP1 variants on the infected erythrocyte membrane. These PfEMP1s contain various combinations of adhesive domains, which allow for the differential engagement of a repertoire of endothelial receptors on the host microvasculature, with specific receptor usage associated with severe disease. We used a co-culture model of cytoadherence incubating human brain microvascular endothelial cells with erythrocytes infected with two parasite lines expressing different PfEMP1s that demonstrate different binding profiles to vascular endothelium. We determined the transcriptional profile of human brain microvascular endothelial cells (HBMEC) following different incubation periods with infected erythrocytes, identifying different transcriptional profiles of pathways previously found to be involved in the pathology of severe malaria, such as inflammation, apoptosis and barrier integrity, induced by the two PfEMP1 variants.

Evolving concepts in the pathophysiology of atherosclerosis: from endothelial dysfunction to thrombus formation through multiple shades of inflammation

Atherosclerosis is the anatomo-pathological substrate of most cardio, cerebro and vascular diseases such as acute and chronic coronary syndromes, stroke and peripheral artery diseases. The pathophysiology of atherosclerotic plaque and its complications are under continuous investigation. In the last 2 decades our understanding on the formation, progression and complication of the atherosclerotic lesion has greatly improved and the role of immunity and inflammation is now well documented and accepted. The conventional risk factors modulate endothelial function determining the switch to a proatherosclerotic phenotype. From this point, lipid accumulation with an imbalance from cholesterol influx and efflux, foam cells formation, T-cell activation, cytokines release and matrix-degrading enzymes production occur. Lesions with high inflammatory rate become vulnerable and prone to rupture. Once complicated, the intraplaque thrombogenic material, such as the tissue factor, is exposed to the flowing blood, thus inducing coagulation cascade activation, platelets aggregation and finally intravascular thrombus formation that leads to clinical manifestations of this disease. Nonconventional risk factors, such as gut microbiome, are emerging novel markers of atherosclerosis. Several data indicate that gut microbiota may play a causative role in formation, progression and complication of atherosclerotic lesions. The gut dysbiosis-related inflammation and gut microbiota-derived metabolites have been proposed as the main working hypothesis in contributing to disease formation and progression. The current evidence suggest that the conventional and nonconventional risk factors may modulate the degree of inflammation of the atherosclerotic lesion, thus influencing its final fate. Based on this hypothesis, targeting inflammation seems to be a promising approach to further improve our management of atherosclerotic-related diseases.

Licorice zinc suppresses melanogenesis via inhibiting the activation of P38MAPK and JNK signaling pathway in C57BL/6J mice skin

PURPOSE

The active melanocytes in the skin were affected by hormones and ultraviolet (UV) irradiation. Licorice zinc has a whitening effect, which may have a prominent potential in the treatment of pigmented skin disease.

METHODS

Modeling chloasma C57BL/6J mice by daily progesterone injection (15 mg/kg) and ultraviolet B (UVB) irradiation (λ = 312 nm, 2 h/day) for 30 days. Then, mice were given 0.65, 1.3, and 2.6 (g/kg) of licorice zinc and tranexamic acid 250 mg daily by oral administration for 14 days, respectively. Hematoxylin and eosin and Fontana-Masson staining, and Western blotting (WB) were performed to test the inhibitory of melanogenesis and activation of c-Jun-N-terminal (JNK)/p38 mitogen-activated protein kinases (MAPK) for licorice zinc. Melanogenesis was induced by α-melanocyte-stimulating hormone in vitro. Cell counting kit-8, melanin content determination, and WB were performed to verify the inhibitory effect of licorice zinc on melanogenesis.

RESULTS

The present study showed that licorice zinc decreased melanin formation, cutaneous tissue injury, and the phosphorylation of JNK and P38MAPK, which was caused by UVB irradiation in vivo. In vitro, licorice zinc showed opposite effects from JNK/p38 activator. Meanwhile, tyrosinase-related protein-1, tyrosinase, and microphthalmia-associated transcription factor were decreased too.

CONCLUSIONS

Licorice zinc induced a decrease in melanin synthesis by inhibiting the JNK and the P38MAPK signaling pathway, suggesting licorice zinc is a potential agent of anti-chloasma.

Bone morphogenetic protein-4 system expression in human coronary artery endothelial and smooth muscle cells under dynamic flow: effect of medicated bioresorbable vascular scaffolds at low and normal shear stress

Endothelial and smooth muscle cell dysfunction is an early event at the onset of atherosclerosis, a heterogeneous and multifactorial pathology of the vascular wall. Bone morphogenetic protein (BMP)-4, a mechanosensitive autocrine cytokine, and BMPR-1a, BMPR-1b, BMPR-2 specific receptors play a key role in atherosclerotic plaque formation and vascular calcification and BMP4 is regarded as a biomarker of endothelial cell activation. The study aimed to examine the BMP4 system expression by Real-Time PCR in Human Coronary Artery Endothelial (HCAECs) and Smooth Muscle Cells (HCASMCs) under different flow rates determining low or physiological shear stress in the presence/absence of medicated Bioresorbable Vascular Scaffold (BVS). The HCAEC and HCASMC were subjected to 1-10-20 dyne/cm² shear stress in a laminar flow bioreactor system, with/without BVS+ Everolimus (600 nM). In HCAECs without BVS the BMP4 expression was similar at 1, 20 dyne/cm² decreasing at 10 dyne/cm², while adding BVS+ Everolimus, it decreased both at 1, 10 compared to 20 dyne/cm². In HCASMCs without BVS + Everolimus, the BMP4 system mRNA expression was significantly reduced at 1, 10 dyne/cm² compared to 20 dyne/cm², while in the presence of BVS+ Everolimus, higher BMP4 mRNA levels were observed at 10 compared to 1, 20 dyne/cm². In HCAECs and HCASMCs BMPRs were expressed in all experimental conditions except for BMPR-1a at 1 dyne/cm² in HCAEC. Significant correlations were found between BMP4 and BMPRs. The more negligible on BMP4 expression due to low shear stress in HCAEC compared to HCASMC and its reduction in the presence of BVS+ Everolimus at low shear stress highlighted the protection of BMP4-mediated against endothelial dysfunction and neoatherogenesis.

Transcriptome analysis reveals fluid shear stress (FSS) and atherosclerosis pathway as a candidate molecular mechanism of short-term low salinity stress tolerance in abalone

Background

Transcriptome sequencing is an effective tool to reveal the essential genes and pathways underlying countless biotic and abiotic stress adaptation mechanisms. Although severely challenged by diverse environmental conditions, the Pacific abalone Haliotis discus hannai remains a high-value aquaculture mollusk and a Chinese predominantly cultured abalone species. Salinity is one of such environmental factors whose fluctuation could significantly affect the abalone’s cellular and molecular immune responses and result in high mortality and reduced growth rate during prolonged exposure. Meanwhile, hybrids have shown superiority in tolerating diverse environmental stresses over their purebred counterparts and have gained admiration in the Chinese abalone aquaculture industry.

The objective of this study was to investigate the molecular and cellular mechanisms of low salinity adaptation in abalone. Therefore, this study used transcriptome analysis of the gill tissues and flow cytometric analysis of hemolymph of H. discus hannai (DD) and interspecific hybrid H. discus hannai ♀ x H. fulgens ♂ (DF) during low salinity exposure. Also, the survival and growth rate of the species under various salinities were assessed.

Results

The transcriptome data revealed that the differentially expressed genes (DEGs) were significantly enriched on the fluid shear stress and atherosclerosis (FSS) pathway. Meanwhile, the expression profiles of some essential genes involved in this pathway suggest that abalone significantly up-regulated calmodulin-4 (CaM-4) and heat-shock protein90 (HSP90), and significantly down-regulated tumor necrosis factor (TNF), bone morphogenetic protein-4 (BMP-4), and nuclear factor kappa B (NF-kB).

Also, the hybrid DF showed significantly higher and sustained expression of CaM and HSP90, significantly higher phagocytosis, significantly lower hemocyte mortality, and significantly higher survival at low salinity, suggesting a more active molecular and hemocyte-mediated immune response and a more efficient capacity to tolerate low salinity than DD.

Conclusions

Our study argues that the abalone CaM gene might be necessary to maintain ion equilibrium while HSP90 can offset the adverse changes caused by low salinity, thereby preventing damage to gill epithelial cells (ECs).

The data reveal a potential molecular mechanism by which abalone responds to low salinity and confirms that hybridization could be a method for breeding more stress-resilient aquatic species.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08611-8.

Targeting endothelial dysfunction and inflammation

Vascular endothelium maintains vascular homeostasis through liberating a spectrum of vasoactive molecules, both protective and harmful regulators of vascular tone, structural remodeling, inflammation and atherogenesis. An intricate balance between endothelium-derived relaxing factors (nitric oxide, prostacyclin and endothelium-derived hyperpolarizing factor) and endothelium-derived contracting factors (superoxide anion, endothelin-1 and constrictive prostaglandins) tightly regulates vascular function. Disruption of such balance signifies endothelial dysfunction, a critical contributor in aging and chronic cardiometabolic disorders, such as obesity, diabetes, hypertension, dyslipidemia and atherosclerotic vascular diseases. Among many proposed cellular and molecular mechanisms causing endothelial dysfunction, oxidative stress and inflammation are often the pivotal players and they are naturally considered as useful targets for intervention in patients with cardiovascular and metabolic diseases. In this article, we provide a recent update on the therapeutic values of pharmacological agents, such as cyclooxygenase-2 inhibitors, renin-angiotensin-system inhibitors, bone morphogenic protein 4 inhibitors, peroxisome proliferator-activated receptor δ agonists, and glucagon-like peptide 1-elevating drugs, and the physiological factors, particularly hemodynamic forces, that improve endothelial function by targeting endothelial oxidative stress and inflammation.

Salvianolic acid B ameliorates vascular endothelial dysfunction through influencing a bone morphogenetic protein 4-ROS cycle in diabetic mice

AIM

This study investigated the roles of bone morphogenetic protein-4 (BMP4) and ROS in diabetic endothelial dysfunction and explored whether Salvianolic acid B (Sal B) improved endothelial function by affecting BMP4-ROS in diabetic mice.

MAIN METHODS

db/db mice were orally administrated with Sal B (10 mg/kg/day) for one week while db/m + mice were injected with adenoviral vectors delivering BMP4 (3 × 10⁸ pfu) and then received one week-Sal B treatment. ROS levels were assayed by DHE staining. Protein expression and phosphorylation were evaluated by Western blot. Aortic rings were suspended in myograph for force measurement. Flow-mediated dilatations in the second-order mesenteric arteries were determined by pressure myograph.

KEY FINDINGS

We first revealed the existence of a BMP4-ROS cycle in db/db mice, which stimulated p38 MAPK/JNK/caspase 3 and thus participated in endothelial dysfunction. One week-treatment or 24 h-incubation with Sal B disrupted the cycle, suppressed p38 MAPK/JNK/caspase 3 cascade, and improved endothelium-dependent relaxations (EDRs) in db/db mouse aortas. Importantly, in vivo Sal B treatment also improved flow-mediated dilatation in db/db mouse second order mesenteric arteries. Furthermore, in vivo BMP4 overexpression induced oxidative stress, stimulated p38 MAPK/JNK/caspase 3, and impaired EDRs in db/m + mouse aortas, which were all reversed by Sal B.

SIGNIFICANCE

The present study demonstrates that Sal B ameliorates endothelial dysfunction through breaking the BMP4-ROS cycle and subsequently inhibiting p38 MAPK/JNK/caspase 3 in diabetic mice and provides evidence for the additional new mechanism underlying the benefit of Sal B against diabetic vasculopathy.

Screening and Identification of Hub Genes in the Corticosteroid Resistance Network in Human Airway Epithelial Cells via Microarray Analysis

Background and Objective: Corticosteroid resistance is a major barrier to chronic obstructive pulmonary disease (COPD), but the exact mechanism of corticosteroid resistance in COPD has been less well studied. Methods: The microarray dataset GSE11906, which includes genomic and clinical data on COPD, was downloaded from the Gene Expression Omnibus (GEO) database, and the differentially expressed genes (DEGs) were identified using R software. Gene set enrichment analysis (GSEA) and Kyoto Encyclopedia of Genes (KEGG) were utilized to enrich and analyze the gene cohort related to the response to steroid hormones, respectively. The Connectivity Map (CMap) database was used to screen corticosteroid resistance-related drugs that might exert a potential therapeutic effect. STRING was used to construct a protein-protein interaction (PPI) network of the gene cohort, and the CytoHubba plug-in of Cytoscape was used to screen the hub genes in the PPI network. The expression levels of hub genes in cigarette smoke extract (CSE)-stimulated bronchial epithelial cells were assayed by quantitative real-time PCR and western blotting. Results: Twenty-one genes were found to be correlated with the response to steroid hormones. In the CMap database, 32 small-molecule compounds that might exert a therapeutic effect on corticosteroid resistance in COPD were identified. Nine hub genes were extracted from the PPI network. The expression levels of the BMP4, FOS, FN1, EGFR, and SPP1 proteins were consistent with the microarray data obtained from molecular biology experiments. Scopoletin significantly restrained the increases in the levels of AKR1C3, ALDH3A1, FN1 and reversed the decreases of phosphorylated GR and HDAC2 caused by CSE exposure. Conclusion: The BMP4, FOS, FN1, EGFR, and SPP1 genes are closely correlated with CSE-induced glucocorticoid resistance in airway epithelial cells. Scopoletin may be a potential drug for the treatment of glucocorticoid resistance caused by CSE.

The Role of Bone Morphogenetic Protein 4 in Ovarian Function and Diseases

Bone morphogenetic proteins (BMPs) are the largest subfamily of the transforming growth factor-β (TGF-β) superfamily. BMP4 is a secreted protein that was originally identified due to its role in bone and cartilage development. Over the past decades, extensive literature has indicated that BMP4 and its receptors are widely expressed in the ovary. Dysregulation of BMP4 expression may play a vital role in follicular development, polycystic ovary syndrome (PCOS), and ovarian cancer. In this review, we summarized the expression pattern of BMP4 in the ovary, focused on the role of BMP4 in follicular development and steroidogenesis, and discussed the role of BMP4 in ovarian diseases such as polycystic ovary syndrome and ovarian cancer. Some studies have shown that the expression of BMP4 in the ovary is spatiotemporal and species specific, but the effects of BMP4 seem to be similar in follicular development of different species. In addition, BMP4 is involved in the development of hyperandrogenemia in PCOS and drug resistance in ovarian cancer, but further research is still needed to clarify the specific mechanisms.

The Phosphodiesterase-5 Inhibitor Vardenafil Improves the Activation of BMP Signaling in Response to Hydrogen Peroxide

PURPOSE

The pleiotropic roles of phosphodiesterase-5 inhibitors (PDE5is) in cardiovascular diseases have attracted attention. The effect of vardenafil (a PDE5i) is partly mediated through reduced oxidative stress, but it is unclear whether vardenafil protects against hydrogen peroxide (H₂O₂)-induced endothelial cell injury, and the molecular mechanisms that are involved remain unknown. We determined the protective role of vardenafil on H₂O₂-induced endothelial cell injury in cultured human umbilical vein endothelial cells (HUVECs).

METHODS AND RESULTS

Vardenafil decreased the number of TUNEL-positive cells, increased the Bcl2/Bax ratio, and ameliorated the numbers of BrdU-positive cells in H₂O₂-treated HUVECs. The bone morphogenetic protein receptor (BMPR)/p-Smad/MSX2 pathway was enhanced in response to H₂O₂, and vardenafil treatment could normalize this pathway. To determine whether the BMP pathway is involved, we blocked the BMP pathway using dorsomorphin, which abolished the protective effects of vardenafil. We found that vardenafil improved the H₂O₂-induced downregulation of BMP-binding endothelial regulator protein (BMPER), which possibly intersects with the BMP pathway in the regulation of endothelial cell injury in response to oxidative stress.

CONCLUSIONS

We demonstrated for the first time that exogenous H₂O₂ activates BMPR expression and promotes Smad1/5/8 phosphorylation. Additionally, vardenafil can attenuate H₂O₂-induced endothelial cell injury in HUVECs. Vardenafil decreases apoptosis through an improved Bcl-2/Bax ratio and increases cell proliferation. Vardenafil protects against endothelial cell injury through ameliorating the intracellular oxidative stress level and BMPER expression. The protective role of vardenafil on H₂O₂-induced endothelial cell injury is mediated through BMPR/p-Smad/MSX2 in HUVECs.

Serum Levels of Bone Morphogenetic Proteins 2 and 4 in Patients with Acute Myocardial Infarction

Background: Bone morphogenetic proteins-2 and -4 (BMPs) have been implicated in left ventricular remodeling (LVR) processes such as an inflammation and fibrogenesis. We hypothesized that this knowledge could be translated into clinics. Methods: We studied the dynamics of serum levels of BMPs, its correlation with markers of LVR and with parameters of echocardiography in patients (n = 31) during the six-month follow-up period after myocardial infarction (MI). Results: Elevated serum levels of BMPs decreased by the six-month follow-up period. BMP-2 decreased from the first day after MI, and BMP-4 decreased from the Day 14. The elevated level of BMP-2 at Day 1 was associated with a lower level of troponin I, reperfusion time and better left ventricular ejection fraction (LV EF) at the six-month follow-up. Elevated serum level of BMP-4 at Day 1 was associated with a lower level of a soluble isoform of suppression of tumorigenicity 2 (sST2), age and reperfusion time. An elevated level of BMP-2 at the six-month follow-up was associated with higher levels of BMP-4, high-sensitivity C-reactive protein (hCRP) and sST2. High serum level of BMP-2 correlated with high levels of hCRP and matrix metalloproteinase (MMP)-9 on Day 7. High serum level of BMP-4 correlated with low levels of hCRP, MMP-9 at Day 3, sST2 at Day 1 and with decreased LV EF on Day 7. The findings of multivariate analysis support the involvement of BMP-2 in the development of post-infarction LVR. Conclusions: Our research translates experimental data about the BMPs in the development of adverse LVR into the clinic. Elevated serum levels of BMPs decreased by the end of the six-month period after MI. BMP-2 decreased from the first day and BMP-4 decreased from Day 14. BMP-2 and BMP-4 were associated with the development of LVR. Their correlations with markers of inflammation, degradation of the extracellular matrix, hemodynamic stress and markers of myocardial damage further support our hypothesis. Diagnostic and predictive values of these BMPs at the development of post-infarction LVR in vivo should be investigated further.

Bone morphogenetic proteins: New insights into their roles and mechanisms in CNS development, pathology and repair

Bone morphogenetic proteins (BMPs) are a highly conserved and diverse family of proteins that play essential roles in various stages of development including the formation and patterning of the central nervous system (CNS). Bioavailability and function of BMPs are regulated by input from a plethora of transcription factors and signaling pathways. Intriguingly, recent literature has uncovered novel roles for BMPs in regulating homeostatic and pathological responses in the adult CNS. Basal levels of BMP ligands and receptors are widely expressed in the adult brain and spinal cord with differential expression patterns across CNS regions, cell types and subcellular locations. Recent evidence indicates that several BMP isoforms are transiently or chronically upregulated in the aged or pathological CNS. Genetic knockout and pharmacological studies have elucidated that BMPs regulate several aspects of CNS injury and repair including cell survival and differentiation, reactive astrogliosis and glial scar formation, axon regeneration, and myelin preservation and repair. Several BMP isoforms can be upregulated in the injured or diseased CNS simultaneously yet exert complementary or opposing effects on the endogenous cell responses after injury. Emerging studies also show that dysregulation of BMPs is associated with various CNS pathologies. Interestingly, modulation of BMPs can lead to beneficial or detrimental effects on CNS injury and repair mechanisms in a ligand, temporally or spatially specific manner, which reflect the complexity of BMP signaling. Given the significance of BMPs in neurodevelopment, a better understanding of their role in the context of injury may provide new therapeutic targets for the pathologic CNS. This review will provide a timely overview on the foundation and recent advancements in knowledge regarding the role and mechanisms of BMP signaling in the developing and adult CNS, and their implications in pathological responses and repair processes after injury or diseases.

Endothelial BMP4 Promotes Leukocyte Rolling and Adhesion and Is Elevated in Patients After Survived Out-of-Hospital Cardiac Arrest

Leukocyte recruitment is a fundamental step in the inflammatory response during ischemia/reperfusion injury (IRI). Rolling and adhesion of leukocytes to activated endothelium promote tissue inflammation after IRI and require presentation of adhesion molecules E-selectin and ICAM-1 on the endothelial surface. Bone morphogenetic protein (BMP) 4 is a prominent member of the BMP family expressed and secreted by endothelial cells. BMP4 derived from endothelial cells has important functions in vascular disease but its influence on the leukocyte adhesion cascade during inflammation is incompletely understood. In the present study, we challenged mice with an inducible endothelial-specific BMP4 deletion (referred to as EC-BMP4^-/- mice) and their control littermates (EC-BMP4^+/+) with thioglycollate i.p. and assessed extravasation of different leukocyte subsets during peritonitis. Peritoneal lavages were performed and peritoneal cells were counted. Total cell count in lavages of EC-BMP4^-/- mice was markedly reduced compared with lavages of EC-BMP4^+/+ mice. FACS analyses of thioglycollate-elicited peritoneal cells revealed that diverse leukocyte subsets were reduced in EC-BMP4^-/- mice. Intravital microscopy of cremaster venules demonstrated that rolling and adhesion of leukocytes were significantly diminished in EC-BMP4^-/- mice in comparison with control mice in response to TNFα. These observations indicate that endothelial BMP4 is essential for rolling, adhesion, and extravasation of leukocytes in vivo. To understand the underlying mechanisms, levels of endothelial adhesion molecules E-selectin and ICAM-1 were quantified in EC-BMP4^-/- and EC-BMP4^+/+ mice by quantitative PCR and Western blotting. Interestingly, ICAM-1 and E-selectin expressions were reduced in the hearts of EC-BMP4^-/- mice. Next we confirmed pro-inflammatory properties of BMP4 in a gain of function experiments and found that administration of recombinant BMP4 in male C57BL/6 mice increased leukocyte rolling and adhesion in cremaster venules in vivo. To assess the regulation of BMP4 in inflammatory disease in humans, we collected plasma samples of patients from day 0 to day 7 after survived out-of-hospital cardiac arrest (OHCA, n = 42). Remarkably, plasma of OHCA patients contained significantly higher BMP4 protein levels compared with patients with coronary artery disease (CAD, n = 12) or healthy volunteers (n = 11). Subgroup analysis revealed that elevated plasma BMP4 levels after ROSC are associated with decreased survival and unfavorable neurological outcome. Collectively, endothelial BMP4 is a potent activator of inflammation in vivo that promotes rolling, adhesion, and extravasation of leukocyte subsets by induction of E-selectin and ICAM-1. Elevation of plasma BMP4 levels in the post-resuscitation period suggests that BMP4 contributes to pathophysiology and poor outcome of post-cardiac arrest syndrome.

Regulation of antioxidant systems in response to anoxia and reoxygenation in Rana sylvatica

The wood frog (Rana sylvatica) is a remarkable species. These frogs can endure prolonged oxygen deprivation as well as dehydration to ~60% of total body water lost and, combining these two abilities, they survive whole body freezing for weeks at a time during the winter. Episodes of anoxia/reoxygenation or freeze/thaw can trigger elevated production of reactive oxygen species (ROS) causing cellular damage, especially when oxygen is reintroduced during reoxygenation or thawing. To mitigate ROS damage, stress-responsive transcription factors such as the Octamer Binding Transcription factor (OCT4) and Nuclear factor (erythroid-derived 2)-like 2 transcription factor (Nrf2) were postulated to be involved in enhancing pro-survival pathways and antioxidant defenses. The present study used immunoblotting to analyze OCT4 and Nrf2 responses (and downstream factors under their control) to 24 h anoxia and 4 h reoxygenation in liver and skeletal muscle of wood frogs, with an emphasis on antioxidant systems. Surprisingly, no change was observed in relative total protein expression of either of the two transcription factors in liver. Furthermore, a significant decrease in total protein levels of OCT4 and Nrf2 occurred in skeletal muscle after 4 h recovery. However, essential cofactors of OCT4 and Nrf2 were significantly upregulated during anoxia and/or recovery. Downstream targets of the Nrf2-ARE pathway were evaluated, including glutathione-S-transferases (GSTs) and aldo-keto reductases (AKRs). Significant increases in GSTT1 and GSTP1 were observed in liver and muscle whereas AKRs showed a tissue specific response to both anoxia and recovery from anoxia. This study demonstrates activation of antioxidants as a cell protective mechanism against generation of reactive oxygen species during anoxia in wood frogs.

Norepinephrine Induces Lung Microvascular Endothelial Cell Death by NADPH Oxidase-Dependent Activation of Caspase-3

Norepinephrine (NE) is the naturally occurring adrenergic agonist that is released in response to hypotension, and it is routinely administered in clinical settings to treat moderate to severe hypotension that may occur during general anesthesia and shock states. Although NE has incontestable beneficial effects on blood pressure maintenance during hypotensive conditions, deleterious effects of NE on endothelial cell function may occur. In particular, the role of reactive oxygen species (ROS) and NADPH oxidase (Nox) on the deleterious effects of NE on endothelial cell function have not been fully elucidated. Therefore, we investigated the effects of NE on ROS production in rat lung microvascular endothelial cells (RLMEC) and its contribution to cell death. RLMEC were treated with NE (5 ng/mL) for 24 hours and ROS production was assessed by CellROX and DCFDA fluorescence. Nox activity was assessed by NADPH-stimulated ROS production in isolated membranes and phosphorylation of p47phox; cell death was assessed by flow cytometry and DNA fragmentation. Caspase activation was assessed by fluorescent microscopy. Nox1, Nox2, and Nox4 mRNA expression was assessed by real-time PCR. NE increased ROS production, Nox activity, p47phox phosphorylation, Nox2 and Nox4 mRNA content, caspase-3 activation, and RLMEC death. Phentolamine, an α₁-adrenoreceptor antagonist, inhibited NE-induced ROS production and Nox activity and partly inhibited cell death while β-blockade had no effect. Apocynin and PEGSOD inhibited NE-induced caspase-3 activation and cell death while direct inhibition of caspase-3 abrogated NE-induced cell death. PEG-CAT inhibited NE-induced cell death but not caspase-3 activation. Collectively, these results indicate that NE induces RLMEC death via activation of Nox by α-adrenergic signaling and caspase-3-dependent pathways. NE has deleterious effects on RLMECs that may be important to its long-term therapeutic use.

Interplay between BMPs and Reactive Oxygen Species in Cell Signaling and Pathology

The integration of cell extrinsic and intrinsic signals is required to maintain appropriate cell physiology and homeostasis. Bone morphogenetic proteins (BMPs) are cytokines that belong to the transforming growth factor-β (TGF-β) superfamily, which play a key role in embryogenesis, organogenesis and regulation of whole-body homeostasis. BMPs interact with membrane receptors that transduce information to the nucleus through SMAD-dependent and independent pathways, including PI3K-AKT and MAPKs. Reactive oxygen species (ROS) are intracellular molecules derived from the partial reduction of oxygen. ROS are highly reactive and govern cellular processes by their capacity to regulate signaling pathways (e.g., NF-κB, MAPKs, KEAP1-NRF2 and PI3K-AKT). Emerging evidence indicates that BMPs and ROS interplay in a number of ways. BMPs stimulate ROS production by inducing NOX expression, while ROS regulate the expression of several BMPs. Moreover, BMPs and ROS influence common signaling pathways, including PI3K/AKT and MAPK. Additionally, dysregulation of BMPs and ROS occurs in several pathologies, including vascular and musculoskeletal diseases, obesity, diabetes and kidney injury. Here, we review the current knowledge on the integration between BMP and ROS signals and its potential applications in the development of new therapeutic strategies.

Effects of l-carnitine supplementation on cardiovascular and bone turnover markers in patients with pemphigus vulgaris under corticosteroids treatment: A randomized, double-blind, controlled trial

Pemphigus vulgaris (PV) is a severe, bullous, autoimmune disease of the skin and mucous membranes. Corticosteroids are usually the main core treatment for controlling PV, which could lead to several side effects such as insulin resistance, osteoporosis, and cardiovascular disorders. The aim of this study is to evaluate the protective effects of l-carnitine (LC) supplementation in PV patients under corticosteroid treatment. In this randomized, double-blind, placebo-controlled clinical trial, 48 patients with PV were divided randomly into two groups to receive 2 g LC (n = 24) or a placebo (n = 24) for 8 weeks, respectively. Serum levels of osteopontin (OPN), bone morphogenic protein 4 (BMP4), cystatin C, systolic and diastolic blood pressure, 25 hydroxyvitamin D3, and LC were evaluated at the beginning and at the end of the study. LC supplementation demonstrated a significant increase in serum carnitine (p < .001). In addition, at the end of the trial, LC supplementation significantly decreased serum BMP4 (p = .003), OPN (p = .03), and cystatin C (p = .001) levels. There was no significant effect on blood pressure in comparison with the placebo. During study, no harmful side effects were reported by patients. These findings indicate that LC supplementation significantly leads to favorable changes in OPN, BMP4, and cystatin C in PV patients under corticosteroid therapy. However, further investigations are required to confirm these results.

TRPC3 Regulates the Proliferation and Apoptosis Resistance of Triple Negative Breast Cancer Cells through the TRPC3/RASA4/MAPK Pathway

Currently, there is no effective molecular-based therapy for triple-negative breast cancer (TNBC). Canonical transient receptor potential isoform 3 (TRPC3) was previously shown to be upregulated in breast cancer biopsy tissues when compared to normal breast tissues. However, the biological role of TRPC3 in breast cancer still remains to be elucidated. In this study, subcellular fractionation followed by Western blot and immunocytochemistry showed that TRPC3 was over-expressed on the plasma membrane of TNBC line MDA-MB-231 when compared to an estrogen receptor-positive cell line MCF-7. TRPC3 blocker Pyr3 and dominant negative of TRPC3 attenuated proliferation, induced apoptosis and sensitized cell death to chemotherapeutic agents in MDA-MB-231 as measured by proliferation assays. Interestingly, Ras GTPase-activating protein 4 (RASA4), a Ca²⁺-promoted Ras-MAPK pathway suppressor, was found to be located on the plasma membrane of MDA-MB-231. Blocking TRPC3 decreased the amount of RASA4 located on the plasma membrane, with concomitant activation of MAPK pathways. Our results suggest that, in TNBC MDA-MB-231 cells, Ca²⁺ influx through TRPC3 channel sustains the presence of RASA4 on the plasma membrane where it inhibits the Ras-MAPK pathway, leading to proliferation and apoptosis resistance. Our study reveals the novel TRPC3-RASA4-MAPK signaling cascade in TNBC cells and suggests that TRPC3 may be exploited as a potential therapeutic target for TNBC.

Bone Morphogenetic Proteins 2/4 Are Upregulated during the Early Development of Vascular Calcification in Chronic Kidney Disease

Vascular calcification is a main cause of increased cardiovascular morbidity and mortality in chronic kidney disease (CKD) patients. This study aimed to investigate the role of the bone morphogenetic protein (BMP) signaling pathway in the early development of vascular calcification in CKD. A CKD vascular calcification rat model was established by providing rats with a 1.8% high-phosphorus diet and an intragastric administration of 2.5% adenine suspension. The kidney and aortic pathologies were analyzed. Blood biochemical indicators, serum BMP-2 and BMP-4 levels, and aortic calcium content were determined. The expression levels of BMP-2, BMP-4, bone morphogenetic protein receptor-IA (BMPR-IA), and matrix Gla protein (MGP) in aorta were examined by quantitative real-time polymerase chain reaction and immunohistochemistry. Compared with the normal control (Nor) rats, the CKD rats exhibited a significantly decreased body weight and an increased kidney weight as well as abnormal renal function and calcium-phosphorus metabolism. Aortic von Kossa and Alizarin red staining showed massive granular deposition and formation of calcified nodules in aorta at 8 weeks. The aortic calcium content was significantly increased, which was positively correlated with the serum BMP-2 (r = 0.929; P < 0.01) and serum BMP-4 (r = 0.702; P < 0.01) levels in CKD rats. The rat aortic BMP-2 mRNA level in the CKD rats was persistently increased, and the BMP-4 mRNA level was prominently increased at the 4th week, declining thereafter. Strong staining of BMP-2, BMP-4, BMPR-IA, and MGP proteins was observed in the tunica media of the aorta from the 4th week after model induction. In conclusion, activation of the BMP signaling pathway is involved in the early development of vascular calcification in CKD. Therefore, elevated serum BMP-2 and BMP-4 levels may serve as serum markers for CKD vascular calcification.

Oligomeric proanthocyanidins protect myocardium by mitigating left ventricular remodeling in isoproterenol-induced postmyocardial infarction

Extracellular matrix (ECM) remodeling is a major pathophysiological process during post-myocardial infarction (MI). The activation, differentiation, and proliferation of cardiac fibroblasts to myofibroblasts regulate the expression of ECM proteins. The signaling by bone morphogenetic protein (BMP-4), an extracellular ligand of the TGF-β family, has recently been identified as an essential pathway in regulating cardiovascular dysfunctions including myocardial fibrosis. Oligomeric proanthocyanidins (OPC) are well known for their cardioprotective activity. The primary aim of the study was to investigate BMP-4-mediated ECM turnover in cardiac fibrosis during isoproterenol-induced post-MI and its downregulation by OPC. Myocardial injury was evaluated by assaying serum markers LDH and CK. Oxidative stress and the enzymatic and nonenzymatic antioxidant levels were assessed to support the cardioprotective nature of OPC. The total collagen level was analyzed by measuring hydroxyproline levels. The ISO-induced group showed a significant decrease in the levels of antioxidants due to severe oxidative stress and increased expression of BMP-4 which reflects the increased expression of MMP 2 and 9 with a concomitant increase and deposition of fibrillary collagens type I and III responsible for the fibrotic scar formation as evidenced in the histological analysis.BMP-4 activation, thus, is strongly associated with cardiac fibrosis which was downregulated upon OPC supplementation. This study provides an evidence supporting the antifibrotic effect of OPC via regulation of BMP-4-mediated ECM turnover and also substantiates the remarkable antioxidant efficacy of OPC against isoproterenol induced severe oxidative stress and subsequent post-MI cardiac fibrosis.

The American cockroach peptide periplanetasin-4 inhibits Clostridium difficile toxin A-induced cell toxicities and inflammatory responses in the mouse gut

Many reports have shown that crude extracts of the American cockroach have therapeutic effects on inflammation. In a previous study, our research group showed that an antimicrobial peptide (Periplanetasin-2) derived from the American cockroach via de novo transcriptome analysis inhibited apoptosis of human colonocytes and inflammatory responses of the mouse gut caused by Clostridium difficile toxin A. Here, we examined whether Periplanetasin-4 (Peri-4), another antimicrobial peptide identified via de novo transcriptome analysis of the American cockroach, could also inhibit the various toxicities induced by C. difficile toxin A. We found that Peri-4 significantly reduced the cell viability loss and cell apoptosis caused by toxin A in vitro. Peri-4 also ameliorated the severe inflammatory responses seen in the toxin A-induced mouse enteritis model, rescuing the villus disruption and interleukin-6 production induced by luminal injection of toxin A into the mouse gut. Mechanistically, we found that Peri-4 could reduce toxin A-induced reactive oxygen species production to inhibit the activations of p38MAPK and p21^Cip1/Waf1 , which are critical for the cell damages induced by toxin A. These results collectively suggest that the Peri-4 may be a potential therapeutic agent for treating toxin A-induced pseudomembranous colitis. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

Phytochemical Investigation, Antitumor Activity, and Hepatoprotective Effects of Acrocarpus fraxinifolius Leaf Extract

Preclinical Research Nine known phenolic compounds were isolated from an aqueous methanolic extract of Acrocarpus fraxinifolius Weight and Arn leaves (AFL) family Fabaceae. This extract of AFL contained approximately 169 mg gallic acid/g as assessed by HPLC. The AFL extract had marginal antitumor activity (IC₅₀  > 200 µL/mL) but showed a concentration-dependent hepatoprotective effect against CCl₄ -induced hepatotoxicity in vitro. Cell viability was increased, ALT and AST activity declined and reduced GSH concentration and SOD activity were restored as compared with silymarin. In vivo concurrent administration of AFL extract (500 mg/kg po) showed a hepatoprotective effect against gamma irradiation and CCl₄ as evidenced by reduction of TNF-α, interleukin-6, malondialdehyde, nitric oxide, DNA fragmentation, caspase-3 activity, and downregulation of its m-RNA level and decreased proapoptotic protein Bax expression. AFL extract enhanced glutathione peroxidase, superoxide dismutase, and catalase activities, reduced glutathione concentrations and upregulated the expression of antiapoptotic Bcl-2. The extract could ameliorate hepatic injuries induced by gamma irradiation and CCl₄ in rats suggesting potent hepatoprotective activity. Drug Dev Res 78 : 210-226, 2017. © 2017 Wiley Periodicals, Inc.

Chronic administration of sodium nitrite prevents hypertension and protects arterial endothelial function by reducing oxidative stress in angiotensin II-infused mice

AIM

Endothelial dysfunction accompanied by an increase in oxidative stress is a key event leading to hypertension. As dietary nitrite has been reported to exert antihypertensive effect, the present study investigated whether chronic oral administration of sodium nitrite improves vascular function in conduit and resistance arteries of hypertensive animals with elevated oxidative stress.

METHODS

Sodium nitrite (50mg/L) was given to angiotensin II-infused hypertensive C57BL/6J (eight to ten weeks old) mice for two weeks in the drinking water. Arterial systolic blood pressure was measured using the tail-cuff method. Vascular responsiveness of isolated aortae and renal arteries was studied in wire myographs. The level of nitrite in the plasma and the cyclic guanosine monophosphate (cGMP) content in the arterial wall were determined using commercially available kits. The production of reactive oxygen species (ROS) and the presence of proteins (nitrotyrosine, NOx-2 and NOx-4) involved in ROS generation were evaluated with dihydroethidium (DHE) fluorescence and by Western blotting, respectively.

RESULTS

Chronic administration of sodium nitrite for two weeks to mice with angiotensin II-induced hypertension decreased systolic arterial blood pressure, reversed endothelial dysfunction, increased plasma nitrite level as well as vascular cGMP content. In addition, sodium nitrite treatment also decreased the elevated nitrotyrosine and NOx-4 protein level in angiotensin II-infused hypertensive mice.

CONCLUSIONS

The present study demonstrates that chronic treatment of hypertensive mice with sodium nitrite improves impaired endothelium function in conduit and resistance vessels in addition to its antihypertensive effect, partly through inhibition of ROS production.

Auranofin Inhibits Retinal Pigment Epithelium Cell Survival through Reactive Oxygen Species-Dependent Epidermal Growth Factor Receptor/ Mitogen-Activated Protein Kinase Signaling Pathway

Abnormal survival of retinal pigment epithelium (RPE) cells contributes to the pathogenesis of proliferative vitreoretinopathy (PVR), a sight-threatening disease. In this study, we explored the effect of the anti-rheumatic agent auranofin (AF) on RPE cell survival and studied the underlying signaling mechanisms in vitro. Our results showed that AF inhibited ARPE-19 cell survival in a dose and time-dependent manner. Application of AF induced several effects: a significant decrease in total epidermal growth factor receptor (EGFR) and an increase in phosphorylated EGFR and mitogen-activated protein kinase (MAPK), including extracellular signal-regulated kinase (ERK), P38 mitogen-activated protein kinase (P38MAPK), c-Jun N-terminal kinase (JNK), c-Jun, mitogen activated protein kinase activated protein kinase 2(MAPKAPK2), and heat shock protein 27 (HSP27). AF also inhibited epidermal growth factor (EGF)-dependent cell proliferation and migration through affecting EGFR/MAPK signaling. The antioxidant N-acetylcysteine (NAC) blocked the AF-induced increase of reactive oxygen species (ROS) production, the reduction of total EGFR, and the phosphorylation of multiple nodes in EGFR/MAPK signaling pathway. P38MAPK inhibitor SB203580, but not inhibitors of EGFR (erlotinib), ERK (FR180204) and JNK (SP600125), suppressed AF-induced phosphorylation of EGFR/p38MAPK/MAPKAPK2/Hsp27. In conclusion, the ROS-dependent phosphorylation of EGFR/MAPK is an important signaling pathway for AF-induced inhibition of RPE cell survival, and AF may have the potential for treatment of abnormal survival of RPE cells in PVR.

PRMT5 is essential for the maintenance of chondrogenic progenitor cells in the limb bud

During embryonic development, undifferentiated progenitor cells balance the generation of additional progenitor cells with differentiation. Within the developing limb, cartilage cells differentiate from mesodermal progenitors in an ordered process that results in the specification of the correct number of appropriately sized skeletal elements. The internal pathways by which these cells maintain an undifferentiated state while preserving their capacity to differentiate is unknown. Here, we report that the arginine methyltransferase PRMT5 has a crucial role in maintaining progenitor cells. Mouse embryonic buds lacking PRMT5 have severely truncated bones with wispy digits lacking joints. This novel phenotype is caused by widespread cell death that includes mesodermal progenitor cells that have begun to precociously differentiate into cartilage cells. We propose that PRMT5 maintains progenitor cells through its regulation of Bmp4 Intriguingly, adult and embryonic stem cells also require PRMT5 for maintaining pluripotency, suggesting that similar mechanisms might regulate lineage-restricted progenitor cells during organogenesis.

A Molecular View of Pathological Microcalcification in Breast Cancer

Breast microcalcification is a potential diagnostic indicator for non-palpable breast cancers. Microcalcification type I (calcium oxalate) is restricted to benign tissue, whereas type II (calcium hydroxyapatite) occurs both in benign as well as in malignant lesions. Microcalcification is a pathological complication of the mammary gland. Over the past few decades, much attention has been paid to exploit this property, which forms the basis for advances in diagnostic procedures and imaging techniques. The mechanism of its formation is still poorly understood. Hence, in this paper, we have attempted to address the molecular mechanism of microcalcification in breast cancer. The central theme of this communication is "how a subpopulation of heterogeneous breast tumor cells attains an osteoblast-like phenotype, and what activities drive the process of pathophysiological microcalcification, especially at the invasive or infiltrating front of breast tumors". The role of bone morphogenetic proteins (BMPs) and tumor associated macrophages (TAMs) along with epithelial to mesenchymal transition (EMT) in manipulating this pathological process has been highlighted. Therefore, this review offers a novel insight into the mechanism underlying the development of microcalcification in breast carcinomas.

Bone Morphogenic Protein 4-Smad–Induced Upregulation of Platelet-Derived Growth Factor AA Impairs Endothelial Function

Objective—

Bone morphogenic protein 4 (BMP4) is an important mediator of endothelial dysfunction in cardio-metabolic diseases, whereas platelet-derived growth factors (PDGFs) are major angiogenic and proinflammatory mediator, although the functional link between these 2 factors is unknown. The present study investigated whether PDGF mediates BMP4-induced endothelial dysfunction in diabetes mellitus.

Approach and Results—

We generated Ad-Bmp4 to overexpress Bmp4 and Ad-Pdgfa-shRNA to knockdown Pdgfa in mice through tail intravenous injection. SMAD4-shRNA lentivirus, SMAD1-shRNA, and SMAD5 shRNA adenovirus were used for knockdown in human and mouse endothelial cells. We found that PDGF-AA impaired endothelium-dependent vasodilation in aortas and mesenteric resistance arteries. BMP4 upregulated PDGF-AA in human and mouse endothelial cells, which was abolished by BMP4 antagonist noggin or knockdown of SMAD1/5 or SMAD4. BMP4-impared relaxation in mouse aorta was also ameliorated by PDGF-AA neutralizing antibody. Tail injection of Ad-Pdgfa-shRNA ameliorates endothelial dysfunction induced by Bmp4 overexpression (Ad-Bmp4) in vivo. Serum PDGF-AA was elevated in both diabetic patients and diabetic db/db mice compared with nondiabetic controls. Pdgfa-shRNA or Bmp4-shRNA adenovirus reduced serum PDGF-AA concentration in db/db mice. PDGF-AA neutralizing antibody or tail injection with Pdgfa-shRNA adenovirus improved endothelial function in aortas and mesenteric resistance arteries from db/db mice. The effect of PDGF-AA on endothelial function in mouse aorta was also inhibited by Ad-Pdgfra-shRNA to inhibit PDGFRα.

Conclusions—

The present study provides novel evidences to show that PDGF-AA impairs endothelium-dependent vasodilation and PDGF-AA mediates BMP4-induced adverse effect on endothelial cell function through SMAD1/5- and SMAD4-dependent mechanisms. Inhibition of PGDF-AA ameliorates vascular dysfunction in diabetic mice.

Bone morphogenetic protein-4: a novel therapeutic target for pathological cardiac hypertrophy/heart failure

Bone morphogenetic protein-4 (BMP4) is a member of the bone morphogenetic protein family which plays a key role in the bone formation and embryonic development. In addition to these predominate and well-studied effects, the growing evidences highlight BMP4 as an important factor in cardiovascular diseases, such as hypertension, pulmonary hypertension and valve disease. Our recent works demonstrated that BMP4 mediated cardiac hypertrophy, apoptosis, fibrosis and ion channel remodeling in pathological cardiac hypertrophy. In this review, we discussed the role of BMP4 in pathological cardiac hypertrophy, as well as the recent advances about BMP4 in cardiovascular diseases closely related to pathological cardiac hypertrophy/heart failure. We put forward that BMP4 is a novel therapeutic target for pathological cardiac hypertrophy/heart failure.

Regulators and effectors of bone morphogenetic protein signalling in the cardiovascular system

Bone morphogenetic proteins (BMPs) play key roles in the regulation of cell proliferation, differentiation and apoptosis in various tissues and organs, including the cardiovascular system. BMPs signal through both Smad-dependent and -independent cascades to exert a wide spectrum of biological activities. Cardiovascular disorders such as abnormal angiogenesis, atherosclerosis, pulmonary hypertension and cardiac hypertrophy have been linked to aberrant BMP signalling. To correct the dysregulated BMP signalling in cardiovascular pathogenesis, it is essential to get a better understanding of how the regulators and effectors of BMP signalling control cardiovascular function and how the dysregulated BMP signalling contributes to cardiovascular dysfunction. We hence highlight several key regulators of BMP signalling such as extracellular regulators of ligands, mechanical forces, microRNAs and small molecule drugs as well as typical BMP effectors like direct downstream target genes, mitogen-activated protein kinases, reactive oxygen species and microRNAs. The insights into these molecular processes will help target both the regulators and important effectors to reverse BMP-associated cardiovascular pathogenesis.

Extracellular regulated protein kinases play a key role via bone morphogenetic protein 4 in high phosphate-induced endothelial cell apoptosis

AIMS

Hyperphosphatemia is an independent risk factor of cardiovascular events in the patients with chronic kidney disease. High phosphate can induce endothelial cell apoptosis, but the exact mechanism is not clear. This study fills this knowledge gap.

MATERIALS AND METHODS

Microarray analysis was used to identify differentially expressed gene profiles in human umbilical vein endothelial cells (HUVECs) in high phosphate (3.0mM) and normal phosphate (1.0mM) medium. Microarray informatics analysis was used to explore key pathways and genes. High phosphate-induced apoptosis is marked by annexin V-FITC/PI staining and cleavage of caspase-3. Immunoblotting and quantitative real-time PCR were performed to identify the microarray analysis.

KEY FINDINGS

Our microarray informatics analysis reveals that the mitogen-activated protein kinase (MAPK) plays a key role. As suggested by gene coexpression network analysis, bone morphogenetic protein 4 (BMP4) gene is a potential key regulatory gene in high phosphate environment. Both the expressions of BMP4 protein and mRNA are decreased. Extracellular regulated protein kinases (ERKs) are activated, while the inhibition of ERK by U0126 increases the expression of BMP4. Both recombinant BMP4 protein pretreatment and U0126 pretreatment reduce the apoptosis of endothelial cells in simulated hyperphosphatemia. However, BMP4 protein pretreatment had no effect on the activation of ERK MAPK pathway.

SIGNIFICANCE

Our results indicate that the inhibition of ERK MAPK pathway protects endothelial cells from apoptosis by upregulating bone morphogenetic protein 4 in endothelial cells exposed to hyperphosphatemia. Our study provides potential molecular targets for developing new strategies to reduce the endothelial cell apoptosis induced by high phosphate.

Boldine improves endothelial function in diabetic db/db mice through inhibition of angiotensin II-mediated BMP4-oxidative stress cascade

BACKGROUND AND PURPOSE

Boldine is a potent natural antioxidant present in the leaves and bark of the Chilean boldo tree. Here we assessed the protective effects of boldine on endothelium in a range of models of diabetes, ex vivo and in vitro.

EXPERIMENTAL APPROACH

Vascular reactivity was studied in mouse aortas from db/db diabetic and normal mice. Reactive oxygen species (ROS) production, angiotensin AT1 receptor localization and protein expression of oxidative stress markers in the vascular wall were evaluated by dihydroethidium fluorescence, lucigenin enhanced-chemiluminescence, immunohistochemistry and Western blot respectively. Primary cultures of mouse aortic endothelial cells, exposed to high concentrations of glucose (30 mmol L(-1) ) were also used.

KEY RESULTS

Oral treatment (20 mg kg(-1) day(-1) , 7 days) or incubation in vitro with boldine (1 μmol L(-1) , 12 h) enhanced endothelium-dependent aortic relaxations of db/db mice. Boldine reversed impaired relaxations induced by high glucose or angiotensin II (Ang II) in non-diabetic mouse aortas while it reduced the overproduction of ROS and increased phosphorylation of eNOS in db/db mouse aortas. Elevated expression of oxidative stress markers (bone morphogenic protein 4 (BMP4), nitrotyrosine and AT1 receptors) were reduced in boldine-treated db/db mouse aortas. Ang II-stimulated BMP4 expression was inhibited by boldine, tempol, noggin or losartan. Boldine inhibited high glucose-stimulated ROS production and restored the decreased phosphorylation of eNOS in mouse aortic endothelial cells in culture.

CONCLUSIONS AND IMPLICATIONS

Boldine reduced oxidative stress and improved endothelium-dependent relaxation in aortas of diabetic mice largely through inhibiting ROS overproduction associated with Ang II-mediated BMP4-dependent mechanisms.

MicroRNAs associated with the efficacy of photodynamic therapy in biliary tract cancer cell lines

Photodynamic therapy (PDT) is a palliative treatment option for unresectable hilar biliary tract cancer (BTC) showing a considerable benefit for survival and quality of life with few side effects. Currently, factors determining the cellular response of BTC cells towards PDT are unknown. Due to their multifaceted nature, microRNAs (miRs) are a promising analyte to investigate the cellular mechanisms following PDT. For two photosensitizers, Photofrin® and Foscan®, the phototoxicity was investigated in eight BTC cell lines. Each cell line (untreated) was profiled for expression of n=754 miRs using TaqMan® Array Human MicroRNA Cards. Statistical analysis and bioinformatic tools were used to identify miRs associated with PDT efficiency and their putative targets, respectively. Twenty miRs correlated significantly with either high or low PDT efficiency. PDT was particularly effective in cells with high levels of clustered miRs 25-93*-106b and (in case of miR-106b) a phenotype characterized by high expression of the mesenchymal marker vimentin and high proliferation (cyclinD1 and Ki67 expression). Insensitivity towards PDT was associated with high miR-200 family expression and (for miR-cluster 200a/b-429) expression of differentiation markers Ck19 and Ck8/18. Predicted and validated downstream targets indicate plausible involvement of miRs 20a*, 25, 93*, 130a, 141, 200a, 200c and 203 in response mechanisms to PDT, suggesting that targeting these miRs could improve susceptibility to PDT in insensitive cell lines. Taken together, the miRNome pattern may provide a novel tool for predicting the efficiency of PDT and-following appropriate functional verification-may subsequently allow for optimization of the PDT protocol.

Bone morphogenic protein-4-induced oxidant signaling via protein carbonylation for endothelial dysfunction

The increased expression of bone morphogenic protein-4 (BMP-4) under hyperglycemic and diabetic conditions mediates the overgeneration of reactive oxygen species to cause endothelial cell dysfunction and apoptosis. Protein carbonylation plays an important role in oxidant signaling through ligand-receptor interactions in vascular smooth muscle cells, cardiac cells, and bronchial smooth muscle cells to trigger different diseases. However, the role of oxidant signaling via protein carbonylation in endothelial dysfunction is unclear. The level of protein carbonylation was higher in renal arteries from diabetic patients than those from nondiabetic subjects. BMP-4 promoted protein carbonylation, which was followed by decarbonylation or degradation in primary rat aortic endothelial cells. Organ culture of normal C57BL/6J mouse aortas treated with either hydralazine or deferoxamine inhibited the effect of BMP-4 on impairment of acetylcholine-induced endothelium-dependent relaxation (EDR). In isolated diabetic db/db mouse aortas, treatment with hydralazine improved the impaired EDR while deferoxamine had no effect. BMP-4-induced carbonylated proteins in aortic endothelial cells were successfully identified by a proteomic approach. These proteins have important cellular functions and include glyceraldehyde-3-phosphate dehydrogenase, triosephosphate isomerase, alpha-enolase, protein disulfide-isomerase A3, annexin II, 26S protease regulatory subunit, integrin-linked protein kinase, and vimentin. Protein carbonylation induced by BMP-4 was inhibited by BMP-4 antagonist while protein decarbonylation induced by BMP-4 was thiol dependent. The carbonyl signals did not involve 4-hydrononenal and malondialdehyde. The present results suggest that BMP-4- or diabetes-mediated endothelial dysfunction is partly triggered through protein carbonylation and blockade of this metal-catalyzed protein oxidation can be considered as an alternative therapeutic strategy to alleviate diabetic vasculopathy.

NOX4 mediates BMP4-induced upregulation of TRPC1 and 6 protein expressions in distal pulmonary arterial smooth muscle cells

Rationale

Our previous studies demonstrated that bone morphogenetic protein 4 (BMP4) mediated, elevated expression of canonical transient receptor potential (TRPC) largely accounts for the enhanced proliferation in pulmonary arterial smooth muscle cells (PASMCs). In the present study, we sought to determine the signaling pathway through which BMP4 up-regulates TRPC expression.

Methods

We employed recombinant human BMP4 (rhBMP4) to determine the effects of BMP4 on NADPH oxidase 4 (NOX4) and reactive oxygen species (ROS) production in rat distal PASMCs. We also designed small interfering RNA targeting NOX4 (siNOX4) and detected whether NOX4 knockdown affects rhBMP4-induced ROS, TRPC1 and 6 expression, cell proliferation and intracellular Ca²⁺ determination in PASMCs.

Results

In rhBMP4 treated rat distal PASMCs, NOX4 expression was (226.73±11.13) %, and the mean ROS level was (123.65±1.62) % of that in untreated control cell. siNOX4 transfection significantly reduced rhBMP4-induced elevation of the mean ROS level in PASMCs. Moreover, siNOX4 transfection markedly reduced rhBMP4-induced elevation of TRPC1 and 6 proteins, basal [Ca²⁺]_i and SOCE. Furthermore, compared with control group (0.21±0.001), the proliferation of rhBMP4 treated cells was significantly enhanced (0.41±0.001) (P<0.01). However, such increase was attenuated by knockdown of NOX4. Moreover, external ROS (H₂O₂ 100 µM, 24 h) rescued the effects of NOX4 knockdown, which included the declining of TRPC1 and 6 expression, basal intracellular calcium concentration ([Ca²⁺]_i) and store-operated calcium entry (SOCE), suggesting that NOX4 plays as an important mediator in BMP4-induced proliferation and intracellular calcium homeostasis.

Conclusion

These results suggest that BMP4 may increase ROS level, enhance TRPC1 and 6 expression and proliferation by up-regulating NOX4 expression in PASMCs.

Tetramethylpyrazine Protects against Hydrogen Peroxide-Provoked Endothelial Dysfunction in Isolated Rat Aortic Rings: Implications for Antioxidant Therapy of Vascular Diseases

Background and Objectives. Oxidative stress can initiate endothelial dysfunction and atherosclerosis. This study evaluated whether tetramethylpyrazine (TMP), the predominant active ingredient in Rhizoma Ligustici Wallichii (chuanxiong), prevents endothelial dysfunction in a rat model of oxidative stress. Methods. Isolated rat aortic rings were pretreated with various drugs before the induction of endothelial dysfunction by hydrogen peroxide (H₂O₂). Changes in isometric tension were then measured in acetylcholine- (ACh-) relaxed rings. Endothelial nitric oxide synthase (eNOS) expression was evaluated in the rings by Western blotting, and superoxide anion (O₂^∙−) content was assessed in primary rat aortic endothelial cells by dihydroethidium- (DHE-) mediated fluorescence microscopy. Results. ACh-induced endothelium-dependent relaxation (EDR) was disrupted by H₂O₂ in endothelium-intact aortic rings. H₂O₂-impaired relaxation was ameliorated by acute pretreatment with low concentrations of TMP, as well as by pretreatment with catalase and the NADPH oxidase inhibitors, apocynin and diphenyleneiodonium (DPI). TMP, apocynin, and DPI also reduced O₂^∙− accumulation in endothelial cells,but TMP failed to alter eNOS expression in aortic rings incubated with H₂O₂. Conclusions. TMP safeguards against oxidative stress-induced endothelial dysfunction, suggesting that the agent might find therapeutic utility in the management of vascular diseases. However, TMP's role in inhibiting NADPH oxidase and its vascular-protective mechanism of action requires further investigation.

The role of BMPs in endothelial cell function and dysfunction

The bone morphogenetic protein (BMP) family of proteins has a multitude of roles throughout the body. In embryonic development, BMPs promote endothelial specification and subsequent venous differentiation. The BMP pathway also plays important roles in the adult vascular endothelium, promoting angiogenesis and mediating shear and oxidative stress. The canonical BMP pathway functions through the Smad transcription factors; however, other intracellular signaling cascades can be activated, and receptor complexes beyond the traditional type I and type II receptors add additional layers of regulation. Dysregulated BMP signaling has been linked to vascular diseases including pulmonary hypertension and atherosclerosis. This review addresses recent advances in the roles of BMP signaling in the endothelium and how BMPs affect endothelial dysfunction and human disease.

Diversity is in my veins: role of bone morphogenetic protein signaling during venous morphogenesis in zebrafish illustrates the heterogeneity within endothelial cells

Endothelial cells are a highly diverse group of cells which display distinct cellular responses to exogenous stimuli. Although the aptly named vascular endothelial growth factor-A signaling pathway is hailed as the most important signaling input for endothelial cells, additional factors also participate in regulating diverse aspects of endothelial behaviors and functions. Given this heterogeneity, these additional factors seem to play a critical role in creating a custom-tailored environment to regulate behaviors and functions of distinct subgroups of endothelial cells. For instance, molecular cues that modulate morphogenesis of arterial vascular beds can be distinct from those that govern morphogenesis of venous vascular beds. Recently, we have found that bone morphogenetic protein signaling selectively promotes angiogenesis from venous vascular beds without eliciting similar responses from arterial vascular beds in zebrafish, indicating that bone morphogenetic protein signaling functions as a context-dependent regulator during vascular morphogenesis. In this review, we will provide an overview of the molecular mechanisms that underlie proangiogenic effects of bone morphogenetic protein signaling on venous vascular beds in the context of endothelial heterogeneity and suggest a more comprehensive picture of the molecular mechanisms of vascular morphogenesis during development.

Protective effect of Korean Red Ginseng against glucocorticoid-induced osteoporosis in vitro and in vivo

Background

Glucocorticoids (GCs) are commonly used in many chemotherapeutic protocols and play an important role in the normal regulation of bone remodeling. However, the prolonged use of GCs results in osteoporosis, which is partially due to apoptosis of osteoblasts and osteocytes. In this study, effects of Korean Red Ginseng (KRG) on GC-treated murine osteoblastic MC3T3-E1 cells and a GC-induced osteoporosis mouse model were investigated.

Methods

MC3T3-E1 cells were exposed to dexamethasone (Dex) with or without KRG and cell viability was measured by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Real-time polymerase chain reaction was performed to evaluate the apoptotic gene expression; osteogenic gene expression and alkaline phosphatase (ALP) activity were also measured. Western blotting was performed to evaluate the mitogen-activated protein kinase (MAPK) proteins. A GC-induced osteoporosis animal model was used for in vivo study.

Results and conclusion

The MTT assay revealed that Korean Red Ginseng (KRG) prevents loss of cell viability caused by Dex-induced apoptosis in MC3T3E1 cells. Real-time polymerase chain reaction data showed that groups treated with both Dex and KRG exhibited lower mRNA levels of caspase-3 and -9, whereas the mRNA levels of Bcl2, IAPs, and XIAP increased. Moreover, groups treated with both Dex and KRG demonstrated increased mRNA levels of ALP, RUNX2, and bone morphogenic proteins as well as increased ALP activity in MC3T3-E1 cells, compared to cells treated with Dex only. In addition, KRG increased protein kinase B (AKT) phosphorylation and decreased c-Jun N-terminal kinase (JNK) phosphorylation. Moreover, microcomputed tomography analysis of the femurs showed that GC implantation caused trabecular bone loss. However, a significant reduction of bone loss was observed in the KRG-treated group. These results suggest that the molecular mechanism of KRG in the GC-induced apoptosis may lead to the development of therapeutic strategies to prevent and/or delay osteoporosis.

Remodeling of rat pulmonary artery induced by chronic smoking exposure

OBJECTIVE

To evaluate the dominant role in rat pulmonary artery (PA) remodeling induced by chronic smoking exposure (CSE).

METHODS

Thirty-five male Sprague-Dawley (SD) rats were exposed to 36 cigarettes per day, 6 days per week, for 1, 3, or 5 months. Another 35 SD rats were sham-exposed during the same period. Hemodynamic measurement, evaluation of the right ventricular hypertrophy index (RVHI) plus right ventricle-to-weight ratio, and hematoxylin eosin staining was performed. Wall thickness, artery radius, luminal area, and total area were measured morphometrically. Western blotting assessed expression of PPAR-γ BMP4, BMPR2, and TRPC1/4/6 in the artery and lung. Store-operated calcium entry (SOCE) and [Ca(2+)]i were measured using Fura-2 as dye.

RESULTS

Mean right ventricular pressure increased after 3 months of smoking exposure and continued to increase through 5 months. Right ventricular systolic pressure (RVSP) increased after 3 months of exposure and then stabilized. RVHI increased after 5 months; right ventricle-to-weight ratio was elevated after 3 months and further increased after 5 months. Wall thickness-to-radius ratio does-dependently increased after 3 months through 5 months, in parallel with the decreased luminal area/total area ratio after 5 months. Other changes included the development of inflammatory responses, enlargement of the alveolar spaces, and reductions in the endothelial lining of PAs, proliferative smooth muscle cells, fibroblasts, and adventitia. Moreover, BMP4 and TRPC1/4/6 expression increased to varying degrees in the arteries and lungs of smoking-exposed animals, whereas BMPR expression and SOCE increased only in the arteries, and PPAR-γ was downregulated in both the arteries and lungs.

CONCLUSIONS

In SD rats, smoking exposure induces pulmonary vascular remodeling. The consequences of increased SOCE include increase in TRPC1/4/6, probably via augmented BMP4 expression, which also contribute to inflammatory responses in the lung. Moreover, interactions between BMP4 and PPAR-γ may play a role in preventing inflammation under normal physiological conditions.

Perturbation of specific pro-mineralizing signalling pathways in human and murine pseudoxanthoma elasticum

Background

Pseudoxanthoma elasticum (PXE) is characterized by skin (papular lesions), ocular (subretinal neovascularisation) and cardiovascular manifestations (peripheral artery disease), due to mineralization and fragmentation of elastic fibres in the extracellular matrix (ECM). Caused by mutations in the ABCC6 gene, the mechanisms underlying this disease remain unknown. The knowledge on the molecular background of soft tissue mineralization largely comes from insights in vascular calcification, with involvement of the osteoinductive Transforming Growth Factor beta (TGFβ) family (TGFβ1-3 and Bone Morphogenetic Proteins [BMP]), together with ectonucleotides (ENPP1), Wnt signalling and a variety of local and systemic calcification inhibitors. In this study, we have investigated the relevance of the signalling pathways described in vascular soft tissue mineralization in the PXE knock-out mouse model and in PXE patients.

Methods

The role of the pro-osteogenic pathways BMP2-SMADs-RUNX2, TGFβ-SMAD2/3 and Wnt-MSX2, apoptosis and ER stress was evaluated using immunohistochemistry, mRNA expression profiling and immune-co-staining in dermal tissues and fibroblast cultures of PXE patients and the eyes and whiskers of the PXE knock-out mouse. Apoptosis was further evaluated by TUNEL staining and siRNA mediated gene knockdown. ALPL activity in PXE fibroblasts was studied using ALPL stains.

Results

We demonstrate the upregulation of the BMP2-SMADs-RUNX2 and TGFβ-2-SMAD2/3 pathway, co-localizing with the mineralization sites, and the involvement of MSX2-canonical Wnt signalling. Further, we show that apoptosis is also involved in PXE with activation of Caspases and BCL-2. In contrast to vascular calcification, neither the other BMPs and TGFβs nor endoplasmic reticulum stress pathways seem to be perturbed in PXE.

Conclusions

Our study shows that we cannot simply extrapolate knowledge on cell signalling in vascular soft tissue calcification to a multisystem ectopic mineralisation disease as PXE. Contrary, we demonstrate a specific set of perturbed signalling pathways in PXE patients and the knock-out mouse model. Based on our findings and previously reported data, we propose a preliminary cell model of ECM calcification in PXE.

High concentraction of taurocholic acid induced apoptosis in HTR-8/SVneo cells via overexpression of ERp29 and activation of p38

INTRODUCTION

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific disease associated with a significant risk of fetal complications. Our previous study using an iTRAQ-based proteomics approach showed that ERp29 was overexpressed in the placenta tissue of ICP patients, which was an apoptosis-related protein and has not been investigated in the pathogenesis of ICP. The aim of this study was to explore the role of ERp29 in the mechanism of apoptosis in the placenta of ICP.

METHODS

HTR-8/SVneo cells were cultured and treated with different concentrations of taurocholic acid (TCA) (0, 10, 50 and 100 μM). The apoptotic index and cell cycle were detected by flow cytometry; furthermore, the expression levels of ERp29 and p-p38 were detected by western blot. The ERp29-siRNA was also used to confirm the role of ERp29 in TCA induced-apoptosis.

RESULTS

ERp29 expression and the apoptotic index were significantly increased in HTR-8/SVneo cells exposed to 100 μM TCA; so were p-p38 and caspase-3 activity, compared with the 50 μM, 10 μM TCA groups and negative control group (P < 0.05, respectively). The induction of apoptosis by TCA and the expression of p-p38 were reduced in HTR-8/SVneo cells after treatment with ERp29-siRNA, compared with controls (P < 0.05, respectively).

CONCLUSIONS

This study suggested that overexpression of ERp29 may play a key role in TCA-induced apoptosis in HTR-8/SVneo cells via activation of p38, which may participate in the pathogenesis of ICP and may represent a novel target for ICP treatment.

Activation of JNKs is essential for BMP9-induced osteogenic differentiation of mesenchymal stem cells

Although BMP9 is highly capable of promoting osteogenic differentiation of mesenchymal stem cell (MSCs), the molecular mechanism involved remains to be fully elucidated. Here, we explore the possible involvement and detail role of JNKs (c-Jun N-terminal kinases) in BMP9-induced osteogenic differentiation of MSCs. It was found that BMP9 stimulated the activation of JNKs in MSCs. BMP9-induced osteogenic differentiation of MSCs was dramatically inhibited by JNKs inhibitor SP600125. Moreover, BMP9-activated Smads signaling was decreased by SP600125 treatment in MSCs. The effects of inhibitor are reproduced with adenoviruses expressing siRNA targeted JNKs. Taken together, our results revealed that JNKs was activated in BMP9-induced osteogenic differentiation of MSCs. What is most noteworthy, however, is that inhibition of JNKs activity resulted in reduction of BMP9-induced osteogenic differentiation of MSCs, implying that activation of JNKs is essential for BMP9 osteoinductive activity. [BMB Reports 2013; 46(8):422-427]

Bone morphogenetic protein-4 induces upregulation of Cav3.1 Ca²⁺ channels in HL-1 atrial myocytes

Cardiac T-type Ca(2+) channels are reexpressed in atrial and ventricular myocytes under various pathological conditions such as post-myocardial infarction, hypertrophy, and heart failure, but relatively little is known about the mechanisms. Our previous study found that bone morphogenetic protein-4 (BMP4) was reexpressed in pathological cardiac hypertrophy models and BMP4-mediated cardiomyocyte hypertrophy. We hypothesized that BMP4 could upregulate cardiac T-type Ca(2+) channels in HL-1 atrial myocytes. The T-type Ca(2+) currents were recorded by using the patch-clamp technique, and the expressions of Cav3.1 and Cav3.2 were measured by real-time PCR method in HL-1 cells. BMP4 and Cav3.1 mRNA expressions increased in the left atrium from the pressure overload-induced hypertrophy of mice hearts. BMP4 treatment for 48 h induced increase of Cav3.1 but not Cav3.2 mRNA expression in HL-1 cells, and the increase was inhibited by BMP4 inhibitor noggin. Acute treatment with BMP4 did not affect T-type Ca(2+) currents, but chronic treatment (48 h) significantly increased the amplitude of T-type Ca(2+) currents in HL-1 cells. Chronic treatment with BMP4 induced upregulation of NADPH oxidase-4 (NOX4), increase of reactive oxygen species (ROS) level, and activation of mitogen-activated protein kinase (MAPK)-activated protein kinases c-jun N-terminal kinases (JNK) and p38. BMP4-induced upregulation of Cav3.1 mRNA was inhibited by NADPH oxidase inhibitor apocynin, the radical scavenger tempol, JNK inhibitor SP600125, and p38 inhibitor SB203580. In conclusion, BMP4 induces upregulation of Cav3.1 Ca(2+) channels and T-type Ca(2+) currents in HL-1 atrial myocytes through ROS/MAPK pathways.

Expression of bone morphogenetic protein 4 and its receptors in the remodeling heart

AIMS

Heart failure is associated with activation of fetal gene programs. Bone morphogenetic proteins (BMPs) regulate embryonic development through interaction with BMP receptors (BMPRs) on the cell surface. We investigated if the expression of BMP4 and its receptors BMPR1a and BMPR2 were activated in post-infarction remodeling and heart failure.

MAIN METHODS

Left ventricular biopsies were taken from explanted hearts of patients with end-stage heart failure due to dilated cardiomyopathy (CMP; n=15) or ischemic heart disease (CAD; n=9), and compared with homograft control preparations from organ donors deceased due to non-cardiac causes (n=7). Other samples were taken from patients undergoing coronary artery bypass grafting (CABG; n=11). Mice were subjected to induced infarction by permanent coronary artery ligation or sham operation, and hearts were sampled serially thereafter (n=7 at each time point).

KEY FINDINGS

Human and mouse hearts expressed BMP4 and both receptor subtypes. CABG and CMP patients had increased expression of mRNA encoding for BMP4, but unchanged protein. Mouse hearts had increased BMP4 precursor protein 24h after infarction. BMPR1a protein decreased in CAD patients and initially in postinfarcted mouse hearts, but increased again in the latter after two weeks. Human recombinant BMP4 promoted survival after H2O2 injury in HL-1 cells, and also protected adult mouse cardiomyocytes against hypoxia-reoxygenation injury.

SIGNIFICANCE

Adult hearts express BMP4, the mRNA increasingly so in patients with coronary artery disease with good cardiac function. BMPRs are downregulated in cardiac remodeling and failure. Recombinant BMP4 has protective effects on cultured cardiomyocytes.

Activation of angiotensin II type 1 receptor-associated protein exerts an inhibitory effect on vascular hypertrophy and oxidative stress in angiotensin II-mediated hypertension

AIMS

Activation of tissue angiotensin II (Ang II) type 1 receptor (AT1R) plays an important role in the development of vascular remodelling. We have shown that the AT1R-associated protein (ATRAP/Agtrap), a specific binding protein of AT1R, functions as an endogenous inhibitor to prevent pathological activation of the tissue renin-angiotensin system. In this study, we investigated the effects of ATRAP on Ang II-induced vascular remodelling.

METHODS AND RESULTS

Transgenic (Tg) mice with a pattern of aortic vascular-dominant overexpression of ATRAP were obtained, and Ang II or vehicle was continuously infused into Tg and wild-type (Wt) mice via an osmotic minipump for 14 days. Although blood pressure of Ang II-infused Tg mice was comparable with that of Ang II-infused Wt mice, the Ang II-mediated development of aortic vascular hypertrophy was partially inhibited in Tg mice compared with Wt mice. In addition, Ang II-mediated up-regulation of vascular Nox4 and p22(phox), NADPH oxidase components, and 4-HNE, a marker of reactive oxygen species (ROS) generation, was significantly suppressed in Tg mice, with a concomitant inhibition of activation of aortic vascular p38MAPK and JNK by Ang II. This protection afforded by vascular ATRAP against Ang II-induced activation of NADPH oxidase is supported by in vitro experimental data using adenoviral transfer of recombinant ATRAP.

CONCLUSION

These results indicate that activation of aortic vascular ATRAP partially inhibits the Nox4/p22(phox)-ROS-p38MAPK/JNK pathway and pathological aortic hypertrophy provoked by Ang II-mediated hypertension, thereby suggesting ATRAP as a novel receptor-binding modulator of vascular pathophysiology.