Unraveling the role of the FHL family in cardiac diseases: Mechanisms, implications, and future directions.

Heart diseases are a major cause of morbidity and mortality worldwide. Understanding the molecular mechanisms underlying these diseases is essential for the development of effective diagnostic and therapeutic strategies. The FHL family consists of five members: FHL1, FHL2, FHL3, FHL4, and FHL5/Act. These members exhibit different expression patterns in various tissues including the heart. FHL family proteins are implicated in cardiac remodeling, regulation of metabolic enzymes, and cardiac biomechanical stress perception. A large number of studies have explored the link between FHL family proteins and cardiac disease, skeletal muscle disease, and ovarian metabolism, but a comprehensive and in-depth understanding of the specific molecular mechanisms targeting FHL on cardiac disease is lacking. The aim of this review is to explore the structure and function of FHL family members, to comprehensively elucidate the mechanisms by which they regulate the heart, and to explore in depth the changes in FHL family members observed in different cardiac disorders, as well as the effects of mutations in FHL proteins on heart health.

Metagenomic and metabolomic analysis showing the adverse risk-benefit trade-off of the ketogenic diet.

BACKGROUND: Ketogenic diets are increasingly popular for addressing obesity, but their impacts on the gut microbiota and metabolome remain unclear. This paper aimed to investigate how a ketogenic diet affects intestinal microorganisms and metabolites in obesity. METHODS: Male mice were provided with one of the following dietary regimens: normal chow, high-fat diet, ketogenic diet, or high-fat diet converted to ketogenic diet. Body weight and fat mass were measured weekly using high-precision electronic balances and minispec body composition analyzers. Metagenomics and non-targeted metabolomics data were used to analyze differences in intestinal contents. RESULTS: Obese mice on the ketogenic diet exhibited notable improvements in weight and body fat. However, these were accompanied by a significant decrease in intestinal microbial diversity, as well as an increase in Firmicutes abundance and a 247% increase in the Firmicutes/Bacteroidetes ratio. The ketogenic diet also altered multiple metabolic pathways in the gut, including glucose, lipid, energy, carbohydrate, amino acid, ketone body, butanoate, and methane pathways, as well as bacterial secretion and colonization pathways. These changes were associated with increased intestinal inflammation and dysbiosis in obese mice. Furthermore, the ketogenic diet enhanced the secretion of bile and the synthesis of aminoglycoside antibiotics in obese mice, which may impair the gut microbiota and be associated with intestinal inflammation and immunity. CONCLUSIONS: The study suggest that the ketogenic diet had an unfavorable risk-benefit trade-off and may compromise metabolic homeostasis in obese mice.

20(S)-Ginsenoside Rh2 inhibits hepatocellular carcinoma by suppressing angiogenesis and the GPC3-mediated Wnt/ß­catenin signaling pathway.

20(S)-Ginsenoside Rh2 has significant anti-tumor effects in various types of cancers, including human hepatocellular carcinoma (HCC). However, its molecular targets and mechanisms of action remain largely unknown. Here, we aim to elucidate the potential mechanisms by which Rh2 suppresses HCC growth. We first demonstrate the role of Rh2 in inhibiting angiogenesis. We observe that Rh2 effectively suppresses cell proliferation and induces apoptosis in HUVECs. Furthermore, Rh2 significantly inhibits HepG2-stimulated HUVEC proliferation, migration and tube formation, accompanied by the downregulation of VEGF and MMP-2 expressions. We also reveal that Rh2 inhibits HCC growth through the downregulation of glypican-3-mediated activation of the Wnt/ß-catenin pathway. We observe a dose-dependent inhibition of proliferation and induction of apoptosis in HepG2 cells upon Rh2 treatment, which is mediated by the inhibition of glypican-3/Wnt/ß-catenin signaling. Moreover, downregulation of glypican-3 expression enhances the effects of Rh2 on the glypican-3/Wnt/ß-catenin signaling pathway, resulting in greater suppression of tumor growth in HepG2 cells. Collectively, our findings shed light on the molecular mechanisms through which Rh2 modulates HCC growth, which involve the regulation of angiogenesis and the glypican-3/Wnt/ß-catenin pathway. These insights may pave the way for the development of novel therapeutic strategies targeting these pathways for the treatment of HCC.

Identification of Potential Indicators for Survival in Patients with Thyroid Cancer Based on Expression of FAM3 Members.

Thyroid cancer (THCA) is a common head and neck malignancy. The family with sequence similarity 3 (FAM3) is a cytokine-like gene family with four members, which is presumed to participate in the development of many cancer types. However, the expression patterns of FAM3s in THCA and their prognostic values, have not yet been established. We investigated differential expressions of FAM3 mRNA and protein in THCA, then validated the findings for FAM3B by immunohistochemistry. We also investigated survival data with respect to FAM3 expression patterns in patients with THCA. FAM3s information regarding their relationships with clinical pathological parameters were obtained and FAM3 mutations were assessed. KEGG and GO pathway regarding FAM3C were obtained using online databases. To investigate potential correlations between FAM3s and immune cell infiltration, we investigated the roles of FAM3s in immune cells of patients with THCA. The mRNA expression of FAM3C were significantly elevated in THCA tissues; high expression levels of FAM3C protein were also observed in THCA tissues. A significant association between the pathological stage and the expression of FAM3C was found in patients with THCA. Patients with THCA who had high mRNA expression levels of FAM3C exhibited significantly more favorable prognosis, compared with patients who had low mRNA expression levels of FAM3C. Overall, FAM3C may play vital roles in the pathogenesis and development of THCA, and these findings constitute novel insights for biomarkers of immunotherapeutic targeted agents and may aid in the identification of prognostic biomarkers for THCA.

Comprehensive Analysis of Tumor Immune Microenvironment and Prognosis of m6A-Related IncRNAs in Lung Adenocarcinoma.

Lung cancer is a fatal disease with high morbidity and mortality. As a major type of non-small cell lung cancer (NSCLC), lung adenocarcinoma (LUAD) has come into the focus of the biological and clinical research. Nevertheless, potential functions of N6-methyladenosine (m6A) methylation-related long non-coding RNAs (lncRNAs) in the tumor immune microenvironment (TIME) remain unclear. Here, we analyzed RNA-seq data of 522 samples from the TCGA-LUAD project. Based on integrative analyses of lncRNA, immune, and clinical profiles, we developed a computational method to determine the characteristics of lncRNAs as an indicators of immune cell infiltration in LUAD patients. Subsequently, we investigated the influence of m6A-related lncRNAs on prognosis and immunotherapy in patients with LUAD. We identified 24 m6A-related lncRNAs that were related to LUAD prognosis and clustered in two molecular subtypes (clusters 1 and 2). Our results suggest that cluster 1 was significantly related to downregulation of PD-L1, enhancement of immune cell infiltration, and good prognosis. Furthermore, p53 and mTOR pathways were enriched in cluster 1, whereas in the cluster 2, PPAR was uncommonly enriched. Patients with LUAD who had lower risk scores exhibited higher immunoscores and lower expression levels of programmed cell death-ligand 1, compared with patients who had higher risk scores. Finally, m6A-related lncRNAs were implicated in the TIME; our findings indicate that these lncRNAs are critical within the TIME in LUAD. These signatures are promising as potential targets for improved LUAD immunotherapy.

Irisin protects against obesity-related chronic kidney disease by regulating perirenal adipose tissue function in obese mice.

BACKGROUND: Compared with typical visceral fat deposits in obesity and metabolic syndrome, perirenal adipose tissue (PRAT) dysfunction is more closely linked to obesity-related chronic kidney disease (OB-CKD). The myokine irisin reportedly promotes positive outcomes in metabolic disease. This study investigated whether irisin could reduce urinary albumin excretion and demonstrate renoprotective effects through the regulation of PRAT function in obese mice. METHODS: C57BL/6 J mice received a high-fat diet (HFD) with or without concurrent administration of irisin. Glucose tolerance, plasma levels of free fatty acids, and urinary albumin excretion were assessed, along with renal morphology. The vascular endothelial growth factor and nitric oxide in glomeruli were also analyzed, in addition to PRAT function-associated proteins. RESULTS: Irisin administration significantly reduced the final body weight, fat mass, and free fatty acids, without reducing PRAT mass, in HFD mice. Furthermore, irisin decreased urinary albumin excretion and attenuated both renal fibrosis and lipid accumulation. Irisin administration led to increases in PRAT function-associated proteins, including sirtuin1, uncoupling protein-1, and heme-oxygenase-1. Ex vivo treatment of PRAT and glomeruli with irisin also restored PRAT function. Finally, irisin treatment restored the vascular endothelial growth factor-nitric oxide axis. CONCLUSIONS: Irisin attenuated metabolic disorders and protected against OB-CKD by normalizing the PRAT-kidney axis. These results suggest that agents targeting PRAT activation might be useful for treatment of OB-CKD.

A paradoxical role for sestrin 2 protein in tumor suppression and tumorigenesis.

Sestrin 2, a highly conserved stress-induced protein, participates in the pathological processes of metabolic and age-related diseases. This p53-inducible protein also regulates cell growth and metabolism, which is closely related to malignant tumorigenesis. Sestrin 2 was reported to regulate various cellular processes, such as tumor cell proliferation, invasion and metastasis, apoptosis, anoikis resistance, and drug resistance. Although sestrin 2 is associated with colorectal, lung, liver, and other cancers, sestrin 2 expression varies among different types of cancer, and the effects and mechanisms of action of this protein are also different. Sestrin 2 was considered a tumor suppressor gene in most studies, whereas conflicting reports considered sestrin 2 an oncogene. Thus, this review aims to examine the literature regarding sestrin 2 in various cancers, summarize its roles in suppression and tumorigenesis, discuss potential mechanisms in the regulation of cancer, and provide a basis for follow-up research and potential cancer treatment development.

Liraglutide ameliorates obesity-related nonalcoholic fatty liver disease by regulating Sestrin2-mediated Nrf2/HO-1 pathway.

Liraglutide, a glucagon-like peptide 1 (GLP-1) analogue, could reverse NAFLD-induced liver damage by improving metabolic profiles, but the exact molecular mechanism has not been elucidated. Sestrin2 is a novel antioxidant protein, essential for regulating metabolic homeostasis. However, whether sestrin2-mediated redox balance participated in the protective effects of liraglutide against NAFLD is still elusive. The aim of the study was to determine whether liraglutide could ameliorate NAFLD by increasing Sestrin2-mediated signaling in obese mice. Following a normal diet or high fat diet (HFD) for 8 weeks, male C57BL/6 mice were treated with or without liraglutide for 4 weeks. Function and histopathology of liver were conducted to evaluate liver injury. Sestrin2-related AMPK and Nrf2/HO-1 pathway were examined. Antioxidative and inflammatory genes and were determined. HFD mice displayed significantly increased body weight, fat mass, lipids levels and impaired glucose homeostasis with reduced glucose tolerance and insulin sensitivity. Metabolic profiles, hepatic injury, and hepatic lipid accumulation from HFD mice were improved by liraglutide treatment. Liraglutide enhanced Sestrin2, phosphorylated AMPK, Nrf2, and HO-1 protein levels. Additionally, Liraglutide treatment increased mRNA levels of Sestrin2, Nrf2, HO-1 and down-stream genes catalase, GCLM and NQO1, but reduced malondialdehyde and TNF-α levels. Our findings indicated that liraglutide ameliorated obesity-related NAFLD through upregulating Sestrin2-mediated Nrf2/HO-1 pathway.

Liraglutide improves obesity-induced renal injury by alleviating uncoupling of the glomerular VEGF-NO axis in obese mice.

Obesity-related kidney disease is associated with generalized endothelial dysfunction. Liraglutide, a glucagon-like peptide-1 agonist, has cardiovascular-renal protective effects in patients with diabetes. In this study, the ability of liraglutide to reduce urinary albumin excretion by alleviating glomerular vascular endothelial growth factor-nitric oxide (VEGF-NO) axis uncoupling was assessed in high fat diet-induced obese mice. C57BL/6J mice were divided into control and obesity groups, treated with or without liraglutide (200 µg/kg/day). Blood biochemistry and urinary albumin excretion were measured. Glomerular VEGF and the AMPK-endothelial nitric oxide synthase (eNOS) pathway were assayed by western blotting. Glomerular NO, renal haeme oxygenase-1 activity, and malondialdehyde levels were also measured. Treatment of obese mice with liraglutide led to significant reductions in body weight gain (46 ± 1 g vs 55 ± 1 g, P < .0001), visceral fat (8.9 ± 0.6 g vs 14.5 ± 0.6 g, P < .0001), perirenal fat (2.9 ± 0.2 g vs 5.4 ± 0.3 g, P < .0001), and free fatty acid (1.71 ± 0.12 mmol/L vs 1.02 ± 0.08 mmol/L, P < .0001). Liraglutide significantly improved glucose homeostasis, which was impaired in obese mice. Liraglutide reduced urinary albumin excretion and glomerular hypertrophy in obese mice. Additionally, liraglutide significantly decreased VEGF and increased glomerular NO production in glomeruli, indicating restoration of the glomerular VEGF-NO axis. Furthermore, liraglutide activated the glomerular AMPK-eNOS pathway in obese mice, upregulated renal haeme oxygenase-1 activity, and reduced the renal malondialdehyde levels in obese mice. In conclusion, liraglutide reduced microalbuminuria and ameliorated renal injury by alleviating the uncoupling of the glomerular VEGF-NO axis.

The Sec domain protein Scfd1 facilitates trafficking of ECM components during chondrogenesis.

Chondrogenesis in the developing skeleton requires transformation of chondrocytes from a simple mesenchymal condensation to cells with a highly enriched extracellular matrix (ECM). This transition is in part accomplished by alterations in the chondrocyte protein transport machinery to cope with both the increased amount and large size of ECM components. In a zebrafish mutagenesis screen to identify genes essential for cartilage development, we uncovered a mutant that disrupts the gene encoding Sec1 family domain containing 1 (scfd1). Homozygous scfd1 mutant embryos exhibit a profound craniofacial abnormality caused by a failure of chondrogenesis. Loss of scfd1 was found to hinder ER to Golgi transport of ECM proteins and is accompanied with activation of the unfolded protein response in chondrocytes. We further demonstrate a conserved role for Scfd1 in differentiation of mammalian chondrocytes, in which loss of either SCFD1 or STX18, a SLY1 interacting t-SNARE, severely impair transport of type II collagen. These results show that the existence of a specific export pathway, mediated by a complex containing SCFD1 and STX18 that plays an essential role in secretion of large ECM proteins during chondrogenesis.

Down-regulation of miR-378a-3p induces decidual cell apoptosis: a possible mechanism for early pregnancy loss.

STUDY QUESTION: Do microRNAs (miRNAs) contribute to human early pregnancy loss (EPL)? SUMMARY ANSWER: miR-378a-3p expression is regulated by progesterone and is down-regulated in ducidua of EPL patients which may contribute to decidual apoptosis through Caspase-3 activation. WHAT IS KNOWN ALREADY: A variety of miRNAs have been demonstrated to be associated with the development of decidualization and placental formation. However, little has been reported on the roles of miRNA in the pathogenesis of EPL. STUDY DESIGN, SIZE, DURATION: Normal and EPL decidual tissues were collected from patients with normal pregnancies undergoing elective termination of gestation, and from patients with EPL, respectively. PARTICIPANTS/MATERIALS, SETTING, METHODS: miRNA microarrays were used to identify the differentially expressed miRNAs between normal and EPL decidua, and miRNA expression was confirmed by qRT-PCR, qRT-PCR, western blotting and luciferase reporter assays were employed to validate the downstream targets of miR-378a-3p. The effects of miR-378a-3p were evaluated using miR-378a-3p-transfected decidual cells. MAIN RESULTS AND THE ROLE OF CHANCE: Of note, 32 up-regulated miRNAs and 38 down-regulated miRNAs were identified by microarray analysis when comparing EPL to normal decidua. MiR-378a-3p was significantly down-regulated in the EPL decidua and was found to inversely regulate the expression of Caspase-3 by directly binding to its 3'-UTRs. In decidual cells, transfection of miR-378a-3p mimics resulted in the inhibition of cell apoptosis and in the increase of cell proliferation through Caspase-3 suppression. Moreover, we found that progesterone could induce the expression of miR-378a-3p in decidual cells. LIMITATIONS, REASONS FOR CAUTION: This study focused on the function of miR-378a-3p and its target Caspase-3, however, numerous other targets and miRNAs may also be responsible for the pathogenesis of EPL. Therefore, further studies are required to elucidate the role of miRNAs in EPL. WIDER IMPLICATIONS OF THE FINDINGS: Our findings indicate that miR-378a-3p may contribute to the development of EPL, and that it could serve as a new potential predictive and therapeutic target of progesterone-treatment for EPL. STUDY FUNDING/COMPETING INTEREST: This study was supported by National Basic Research Program of China (No.2012CB944900); National Science Foundation of China (No.31471405 and 81490742, No.81361120246); The National Science and Technology Support Program (No.2012BA132B00). Authors declare no competing interests.

C1q/TNF-related protein 9 improves the anti-contractile effects of perivascular adipose tissue via the AMPK-eNOS pathway in diet-induced obese mice.

The anti-contractile property of perivascular adipose tissue (PVAT) is abolished through an endothelium-dependent pathway in obesity. C1q/tumor necrosis factor-related protein (CTRP)9 improved endothelial function by promoting endothelium-dependent vasodilatation. The aims of this study were to investigate whether CTRP9 improves the anti-contractile effect of PVAT and protects against PVAT dysfunction in obese mice. The mice were treated with a high-fat diet with or without CTRP9 treatment. Thoracic aortas with or without PVAT (PVAT+ or PVAT-) were prepared, and concentration-dependent responses to phenylephrine were measured. Obese mice showed a significantly increased contractile response, which was suppressed by CTRP9 treatment both with and without PVAT. PVAT significantly reduced the anti-contractile effect in obese mice, which was partially restored by CTRP9 treatment. Treatment of the aortic rings (PVAT+) with inhibitors of AMP protein kinase (AMPK), Akt and endothelial nitric oxide synthase (eNOS) attenuated the beneficial effect of CTRP9 on PVAT. Similar results were observed when we pretreated the aortic rings with CTRP9 ex vivo. CTRP9 significantly enhanced the phosphorylation levels of AMPK, Akt and eNOS, and reduced superoxide production and TNF-α levels in PVAT from obese mice. Our study suggests that CTRP9 enhanced the anti-contractile effect of PVAT and improved PVAT function by activating the AMPK-eNOS pathway in obese mice.

Irisin Regulates Heme Oxygenase-1/Adiponectin Axis in Perivascular Adipose Tissue and Improves Endothelial Dysfunction in Diet-Induced Obese Mice.

AIMS: To determine whether irisin could improve endothelial dysfunction by regulating heme oxygenase-1(HO-1)/adiponectin axis in perivascular adipose tissue (PVAT) in obesity. METHODS: Male C57BL/6 mice were fed with a high-fat diet (HFD) with or without irisin treatment. Endothelium-dependent vasorelaxation of the thoracic aorta with or without PVAT (PVAT+ or PVAT-) was determined. Western blot was employed to determine the levels of HO-1 and adiponectin in PVAT. UCP-1, Cidea, and TNF-α gene expression in PVAT were tested by real-time PCR. RESULTS: The presence of PVAT significantly impaired endothelial function in the HFD mice. Treatment of HFD mice with irisin significantly restored this impairment and improved endothelial function in vivo or ex vivo. Incubated aortic rings (PVAT-) with PVAT-derived conditioned medium (CM) from HFD mice impaired endothelial function in control mice. This impairment was prevented by incubating the aortic rings (PVAT-) from HFD mice with PVAT-derived CM from irisin. However, the beneficial effects were partly attenuated in the presence of HO-1 inhibitor and adiponectin receptor blocking peptide. Treatment of HFD mice with irisin significantly increased NO production, protein levels of HO-1 and adiponectin, mRNA expressions of UCP-1 and Cidea, and decreased superoxide production and TNF-α expression in PVAT. CONCLUSION: Irisin improved endothelial function by modulating HO-1/ adiponectin axis in PVAT in HFD-induced obese mice. These findings suggest that regulating PVAT function may be a potential mechanism by which irisin improves endothelial function in obesity.

Irisin improves perivascular adipose tissue dysfunction via regulation of the heme oxygenase-1/adiponectin axis in diet-induced obese mice.

AIMS: To determine whether irisin could improve perivascular adipose tissue (PVAT) dysfunction via regulation of the heme oxygenase-1 (HO-1)/adiponectin axis in obesity. MATERIALS AND METHODS: C57BL/6 mice were given chow or a high-fat diet (HFD) with or without treatment with irisin. The concentration-dependent responses of the thoracic aorta with or without PVAT (PVAT+ or PVAT-) to phenylephrine were studied in an organ bath. Protein levels of HO-1 and adiponectin were determined by western blot. UCP-1, Cidea, and TNF-α gene expression in PVAT were analyzed by real-time PCR. RESULTS: Treatment of obese mice with irisin improved glucose and lipid metabolism, reduced plasma levels of TNF-α and malondialdehyde, and increased plasma adiponectin levels (P<0.01). The anti-contractile effects of PVAT were attenuated in HFD mice and this attenuation was restored in HFD mice treated with irisin (P<0.05). Incubation of aortas (PVAT+) with the HO-1 inhibitor and adiponectin receptor blocking peptide in irisin-treated HFD mice abolished the beneficial effects of irisin on PVAT function. The same results were also observed in HFD mice treated with irisin ex vivo. Treatment of HFD mice with irisin significantly enhanced protein levels of HO-1 and adiponectin, and reduced superoxide production and TNF-α expression in PVAT. Irisin treatment enhanced brown adipocyte markers UCP-1 and Cidea expression in PVAT from HFD mice. CONCLUSION: Irisin improved the anti-contractile properties of PVAT from the thoracic aorta in diet-induced obese mice. The mechanism for protective effects of irisin appeared to be related to upregulation of the HO-1/adiponectin axis in PVAT and browning of PVAT.

Association between premature ovarian failure, polymorphisms in MTHFR and MTRR genes and serum homocysteine concentration.

This study investigated the association between premature ovarian failure (POF), MTHFR C677T/A1298C and MTRR A66G genotypes and serum homocysteine (Hcy) concentration. A prospective study was conducted in Chinese women, which included POF patients (n = 180) and controls (n = 195). Peripheral blood samples were used to determine MTHFR C677T/A1298C and MTRR A66G genotypes, and serum Hcy and sex hormone concentrations. Results showed that serum Hcy concentrations of POF patients were significantly higher than those of controls (P < 0.0001). In POF patients, serum Hcy concentrations were significantly correlated with oestradiol and FSH concentrations (r = -0.174, P = 0.037 and r = +0.238, P = 0.006, respectively). There were no significant differences in the distributions of MTHFR C677T/A1298C or MTRR A66G genotypes between the two groups. However, these genetic variants influenced serum Hcy concentrations in POF patients, especially for MTRR 66 AA/AG/GG genotypes, which were significantly correlated with the patients' Hcy concentrations (τ = 0.166, P = 0.033). These results suggest that serum Hcy concentrations in Chinese POF patients are increased and correlated with serum oestradiol/FSH concentrations. In conclusion, MTHFR C667T/A1298C and MTRR A66G genotypes are not associated with POF development, but they affect the patients' serum Hcy concentrations.

Irisin improves endothelial function in obese mice through the AMPK-eNOS pathway.

Irisin is a novel hormone secreted by myocytes. Lower levels of irisin are independently associated with endothelial dysfunction in obese subjects. The objective of this study was to explore whether irisin exerts a direct vascular protective effect on endothelial function in high-fat-diet-induced obese mice. Male C57BL/6 mice were given chow or a high-fat diet with or without treatment with irisin. Aortic endothelial function was determined by measuring endothelium-dependent vasodilatation (EDV). Nitric oxide (NO) in the aorta was determined. The effect of irisin on the levels of AMP-activated protein kinase (AMPK), Akt, and endothelial NO synthase (eNOS) phosphorylation in endothelial cells was determined. Human umbilical vein endothelial cells were used to study the role of irisin in the AMPK-eNOS pathway. Acetylcholine-stimulated EDV was significantly lower in obese mice compared with control mice. Treatment of obese mice with irisin significantly enhanced EDV and improved endothelial function. This beneficial effect of irisin was partly attenuated in the presence of inhibitors of AMPK, Akt, and eNOS. Treatment of obese mice with irisin enhanced NO production and phosphorylation of AMPK, Akt, and eNOS in endothelial cells. These factors were also enhanced by irisin in human umbilical vein endothelial cells in vitro. Suppression of AMPK expression by small interfering RNA blocked irisin-induced eNOS and Akt phosphorylation and NO production. We have provided the first evidence that irisin improves endothelial function in aortas of high-fat-diet-induced obese mice. The mechanism for this protective effect is related to the activation of the AMPK-eNOS signaling pathway.

Induction of haemeoxygenase-1 improves FFA-induced endothelial dysfunction in rat aorta.

BACKGROUND: The induction of haemeoxygenase-1 (HO-1) exerts beneficial effects in the setting of endothelial dysfunction in obesity. High free fatty acid (FFA) levels are a common feature of obesity and are the primary cause of endothelial dysfunction. The objective of our study was to explore the effects of HO-1 induction on FFA-induced endothelial dysfunction in rats. METHODS: Rats received FFA treatment with either cobalt protoporphyrin (CoPP) to induce HO-1 or stannous protoporphyrin (SnPP) to inhibit HO-1. Endothelial function was determined by measuring endothelium-dependent vasodilatation (EDV). Nitric oxide (NO) production, superoxide production and nuclear factor (NF)-κB expression in the aorta were each determined. The levels of adenosine monophosphate (AMP)-activated kinase (AMPK) and endothelial nitric oxide synthase (eNOS) expression in endothelial cells were determined via Western blotting. RESULTS: Induction of HO-1 by CoPP decreased circulating FFA, high-sensitivity C-reactive protein and malondialdehyde levels and increased serum adiponectin and glutathione levels compared with the FFA group (P<0.05). High FFA levels resulted in EDV impairment, which was improved by HO-1 induction (P<0.05). Induction of HO-1 increased NO levels and reduced aortic superoxide production and NF-κB expression compared with the FFA group. The FFA group exhibited decreased AMPK expression and eNOS phosphorylation, both of which were enhanced via HO-1 induction (P<0.05). The beneficial effects of CoPP on EDV were partially attenuated in vitro in the presence of inhibitors of AMPK, phosphatidylinositol 3-kinase (PI3K), and eNOS. CONCLUSIONS: HO-1 induction with CoPP improves FFA-induced endothelial dysfunction in the rat aorta. The protective mechanism appears to be related to the activation of the AMPK-PI3K-eNOS pathway as a result of increased adiponectin levels as well as decreased inflammation and oxidative stress.

Induction of Haemeoxygenase-1 Directly Improves Endothelial Function in Isolated Aortas from Obese Rats through the Ampk-Pi3k/Akt-Enos Pathway.

BACKGROUND: Induction of haemeoxygenase-1 (HO-1) increases adiponectin secretion by remodeling adipose tissue in obesity. The objective of our study is to explore whether HO-1 induction directly improves endothelial function independent of adiponectin changes in obese rats. METHODS: Rats were divided into control and obesity groups. Aortic endothelial function was determined by measuring endothelium-dependent vasodilatation (EDV). Vascular segments of the obese rats were incubated in an organ bath in the presence or absence of cobalt protoporphyrin (CoPP) or CoPP plus stannous protoporphyrin. Nitric oxide (NO) production, superoxide anion production and NF-κB p65 expression in the aorta were determined. The expression of AMP-activated kinase (AMPK), Akt and endothelial nitric oxide synthase (eNOS) in endothelial cells was determined by western blotting. The aortic rings from the obese rats were then incubated with CoPP in the presence of specific inhibitors of AMPK, phosphatidylinositol 3-kinase (PI3K) or eNOS. RESULTS: Acetylcholine-induced EDV was significantly attenuated in the obese rats, compared with the NC group (p < 0.05). Pre-incubation of vessels from obese rats with CoPP significantly increased EDV (p < 0.05). However, this beneficial effect of CoPP was partly attenuated in vitro in the presence of inhibitors of AMPK, PI3K or eNOS. HO-1 induction with CoPP significantly increased the activation of the AMPK-PI3K/Akt-eNOS pathway and NO production in parallel with reduced superoxide anion production and NF-κB p65 expression in obese rats. CONCLUSIONS: HO-1 induction with CoPP directly improved endothelial function in obese rats independent of adiponectin changes. The mechanism of this protective effect is related to increasing NO production by activation of the AMPK-PI3K/Akt-eNOS signaling pathway.

The relationship between circulating irisin levels and endothelial function in lean and obese subjects.

OBJECTIVE: Irisin has been shown to turn white adipocytes into brown-like adipocytes, which is emerging as an appealing therapeutic target for obesity. The objective of the study was to determine whether circulating irisin levels are related to endothelial dysfunction in obese subjects. DESIGN: A total of 41 nonhypertensive, nondiabetic obese subjects and 40 age- and sex-matched lean healthy control were involved in this study. Clinical characteristics, blood biochemistry, circulating irisin and adiponectin of the subjects were measured. Endothelium-dependent vasodilation (EDV) and endothelial-independent vasodilation (EIV) were determined using high-resolution ultrasound. RESULTS: Circulating irisin and adiponectin were significantly lower in obese subjects compared with lean healthy control (P < 0·05). Endothelial function was impaired in obese subjects (maximum EDV: 8·95 ± 3·46% vs 14·56 ± 3·90%, P < 0·05). Bivariate correlation analysis revealed that circulating irisin was positively correlated with EDV(r = 0·388, P < 0·01) and negatively correlated with BMI (r = -0·281, P < 0·05), waist circumference (r = -0·298, P < 0·01), free fatty acid (FFA) (r = -0·289, P < 0·01), high-sensitivity C-reactive protein (hs-CRP) (r = -0·244, P < 0·05) and malondialdehyde (r = -0·258, P < 0·05). Multiple regression analysis revealed that circulating irisin, adiponectin, FFA and BMI were independently associated with EDV after adjusting for covariates (R(2) = 0·457, F = 8·766, P = 0·000). CONCLUSIONS: Circulating irisin level was decreased in nonhypertensive, nondiabetic obese subjects compared with lean healthy control. Lower levels of irisin are independently associated with endothelial dysfunction. Therefore, irisin may be involved in the regulation of endothelial function in obesity.

Renal protective effects of induction of haem oxygenase-1 combined with increased adiponectin on the glomerular vascular endothelial growth factor-nitric oxide axis in obese rats.

NEW FINDINGS: What is the central question of this study? This study aimed to investigate whether induction of haem oxygenase-1 (HO-1) can protect the kidneys of obese rats by regulating the glomerular vascular endothelial growth factor-nitric oxide (VEGF-NO) axis by increasing the adiponectin concentrations. What is the main finding and its importance? Induction of HO-1 reduces the degree of microalbuminuria and has renal protective effects by improving endothelial function and regulating the uncoupled glomerular VEGF-NO axis in diet-induced obese rats. The mechanism may be related to increased activation of the HO-1-adiponectin axis. The glomerular vascular endothelial growth factor-nitric oxide (VEGF-NO) axis plays a critical role in maintenance of normal kidney function in obesity. Induction of haem oxygenase-1 (HO-1) may result in a parallel increase in adiponectin secretion. The aim of this study was to investigate whether induction of HO-1 could protect the kidneys of obese rats by regulating the glomerular VEGF-NO axis by increasing adiponectin levels. Rats received high-fat diets and were injected with either cobalt protoporphyrin to induce HO-1 or stannous protoporphyrin to inhibit HO-1. Blood and urine samples were collected. Endothelial function was determined by measuring the endothelium-dependent vasodilatation of the aorta. Renal tissues were collected for CD34 immunohistochemistry. The glomerular VEGF-NO axis and the AMP kinase-phosphoinositide 3-kinase (PI3K)/Akt-endothelial nitric oxide synthase pathway were measured. Induction of HO-1 by cobalt protoporphyrin decreased microalbuminuria, plasma free fatty acids, serum high-sensitivity C-reactive protein and malondialdehyde levels and increased serum adiponectin levels compared with the untreated obese rats. Severe impairment of endothelium-dependent vasodilatation was observed in the obese rats, which was improved to some extent by HO-1 induction. Induction of HO-1 reduced glomerular CD34 expression and production of reactive oxygen species in obese rats. Obese rats showed increased glomerular VEGF expression and reduced NO levels. This uncoupling of the glomerular VEGF-NO axis was improved to some extent by induction of HO-1, with enhancement of p-AMP kinase, p-Akt and phospho-endothelial nitric oxide synthase in obese rats. These results indicate that induction of HO-1 with cobalt protoporphyrin reduces the degree of microalbuminuria and has renal protective effects by improving endothelial dysfunction and regulating the glomerular VEGF-NO axis in diet-induced obese rats by increasing adiponectin levels.