FGF21 Prevents Angiotensin II-Induced Hypertension and Vascular Dysfunction by Activation of ACE2/Angiotensin-(1-7) Axis in Mice

Circulating fibroblast growth factor 21 is associated with blood pressure in the Chinese population: a community-based study

BACKGROUND

Our research team previously found that fibroblast growth factor (FGF) 21, a circulating hormone, was significantly associated with atherosclerosis in human and animal models. The relationship between FGF21 and blood pressure (BP) is rarely studied in the Asian population. Therefore, we aimed to explore the relationship of FGF21 with BP in a Chinese population.

METHODS

We analysed data on 1051 participants from the Shenzhen-Hong Kong United Network on Cardiovascular Disease (SHUN-CVD) study.

RESULTS

The medians of FGF21 level were 355.1 pg/mL (IQR 234.3-574.8 pg/mL) for hypertensive patients and 253.5 (IQR 136.9-403.3 pg/mL) for non-hypertensive participants. Ln-transformed FGF21 level was associated with both systolic and diastolic BP (systolic BP: B = 4.45 [95% CI 3.41-5.49]; p < .001; diastolic BP: B = 2.72 [95% CI 2.03-3.42]; p < .001). After adjusting for sex, age, body mass index, hypercholesterolaemia, diabetes, alcohol consumption, smoking and physical activity, the association remained significant (systolic BP: B = 1.99 [95% CI 1.01-2.97]; p < .001; diastolic BP: B = 1.36 [95% CI 0.69-2.04]; p < .001). Serum FGF21 level was associated with hypertension (quartile 4 vs. quartile 1, OR = 4.19 [95% CI 2.65-6.61]; p for trend < .001).

CONCLUSIONS

This is the first study to elucidate the relationship of FGF21 with BP in the Asian population. FGF21 is significantly associated with BP. Besides its use as a biomarker, FGF21 may be a new drug target for hypertension treatment.

Hepatocyte-specific RAP1B deficiency ameliorates high-fat diet-induced obesity and liver inflammation in mice

AIM

This study investigated the role of RAP1B in hepatic lipid metabolism and its implications in obesity and associated metabolic disorders, focusing on the molecular mechanisms through which RAP1B influences lipid accumulation, inflammation and oxidative stress in liver tissues and hepatocyte cell lines.

MATERIALS AND METHODS

Liver-specific RAP1B-knockout (LKO) and overexpression (OE) mice were generated and fed a high-fat diet for 18 weeks to evaluate systemic and hepatic metabolic changes. Comprehensive metabolic phenotyping included measurements of body weight, body fat content, activity levels, energy expenditure (EE), respiratory exchange ratio (RER), glucose tolerance test and insulin tolerance test. RAP1B-knockdown AML12 hepatocytes were used for in vitro studies. Comprehensive transcriptome and metabolome analyses identified differentially expressed genes and key metabolic shifts. Biochemical and histological analyses were performed to assess lipid accumulation, oxidative stress and inflammatory markers.

RESULTS

We found that LKO mice exhibited significant reductions in body weight, fat pad size and liver mass, along with decreased hepatic lipid accumulation due to enhanced lipid breakdown. These mice demonstrated improved glucose tolerance and insulin sensitivity without changes in food intake. Liver histology showed reduced F4/80-positive macrophage infiltration, indicating decreased inflammatory cell recruitment. Additionally, markers of oxidative stress were significantly lower, and molecular analysis revealed downregulation of the MAPK(p38) and NF-κB signaling pathways, further supporting an anti-inflammatory hepatic environment. In contrast, OE mice showed increased liver weight, aggravated hepatic lipid accumulation driven by enhanced lipogenesis, worsened insulin resistance and elevated inflammation.

CONCLUSIONS

This study highlights RAP1B's pivotal role in hepatic metabolism and positions it as a potential therapeutic target for obesity and related metabolic disorders.

Sodium-Glucose Cotransporter 2 Inhibitor Ameliorate Angiotensin II-Induced Hypertension and Vascular Injury by Upregulating FGF21

Clinical trials have demonstrated Sodium-glucose cotransporter 2 inhibitors (SGLT2i) antihypertensive effects, yet their underlying mechanisms remain to be fully elucidated. Fibroblast growth factor 21 (FGF21) circulating levels are associated with hypertension in humans. This study aims to investigate the roles of SGLT2i and FGF21 in improving hypertension and their potential mechanisms. A mouse model of Ang II-induced hypertension was established. Wild-type (WT) C57BL/6 mice and FGF21 knockout (FGF21-/-) mice were sequentially treated with Angiotensin II (Ang II) and dapagliflozin. Blood pressure was monitored. Cardiac structure was assessed using echocardiography. Serum FGF21 levels were measured, and the expression of fibroblast growth factor receptor 1 (FGFR1) in the thoracic aorta was quantified. Vascular pathology and oxidative stress responses were evaluated. Human aortic smooth muscle cells (HASMCs) were treated with Ang II or SGLT2i, and FGF21 was knocked down in HASMCs to explore its mechanism of action. SGLT2i increased the expression of FGF21 and FGFR. SGLT2i improved Ang II-induced systolic blood pressure elevation, myocardial hypertrophy, vascular wall thickening, fibrosis, and oxidative stress in WT mice. These protective effects were reduced in FGF21-/- mice. Knockdown of FGF21 in HASMCs abolished the SGLT2i-induced upregulation of antioxidant markers and the downregulation of TGF-β and fibrosis-related proteins. SGLT2i-mediated blood pressure-lowering and vascular protective effects are primarily achieved through the activation of the FGF21/FGFR1.

Unlocking the potential of the ACE2/Ang-(1-7)/Mas Axis in liver diseases: From molecular mechanisms to translational applications

Over the past two decades, the identification of new functions within the renin-angiotensin system (RAS) has extended beyond its traditional roles, with the emergence of the angiotensin-converting enzyme 2 (ACE2)/Ang-(1-7)/Mas axis being particularly significant. This axis is hypothesized to balance or modulate the effects of the traditional ACE/Ang II/AT1 axis in various physiological and pathological contexts. ACE2, a membrane-bound carboxypeptidase and an ancient homologue of ACE converts Angiotensin II (Ang II) into Angiotensin 1-7 (Ang-(1-7)). The Mas receptor is a G-protein-coupled receptor that specifically binds Ang-(1-7). Recent research has increasingly focused on the local expression of RAS in different tissues. Ang-(1-7) produces a variety of biological effects by binding to the Mas receptor, including anti-inflammatory, antioxidant, anti-apoptotic and anti-fibrotic actions, thereby influencing a range of mechanisms in the heart, kidneys, brain and other tissues. Preclinical animal model studies indicate that manipulating the protective RAS can significantly alter the progression of multiple liver diseases. Hepatic overexpression of ACE2 or administration of Ang-(1-7) and its analogues has been shown to be therapeutically effective against drug-induced liver injury, metabolic-associated fatty liver disease, liver fibrosis and hepatocellular carcinoma progression. These effects are achieved through various pathways, including the regulation of lipid metabolism, inhibition of epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) production, as well as suppression of aerobic glycolysis. In current clinical trials, while recombinant human ACE2 (Rh-ACE2) has demonstrated safety and good tolerance in most studies, research on the relevance of activating the ACE2/Ang-(1-7) axis in the mechanisms and evolution of human diseases remains in its early stages. Therefore, further elucidation of the complex interactions between the classical and counter-regulatory RAS axes in clinical settings is crucial. This review will summarize the roles of selective activation of the ACE2/Ang-(1-7)/Mas axis, with a focus on its mechanisms in the treatment of liver diseases. Additionally, we will discuss the safety concerns regarding selective activation of the ACE2/Ang-(1-7)/Mas axis in clinical applications and the challenges of tissue-specific activation of this axis, providing effective therapeutic strategies for targeted activation of the hepatic ACE2/Ang-(1-7)/Mas axis in clinical practice.

FGF-based drug discovery: advances and challenges

The fibroblast growth factor (FGF) family comprises 15 paracrine-acting and 3 endocrine-acting polypeptides, which govern a multitude of processes in human development, metabolism and tissue homeostasis. Therapeutic endocrine FGFs have recently advanced in clinical trials, with FGF19 and FGF21-based therapies on the cusp of approval for the treatment of primary sclerosing cholangitis and metabolic syndrome-associated steatohepatitis, respectively. By contrast, while paracrine FGFs were once thought to be promising drug candidates for wound healing, burns, tissue repair and ischaemic ailments based on their potent mitogenic and angiogenic properties, repeated failures in clinical trials have led to the widespread perception that the development of paracrine FGF-based drugs is not feasible. However, the observation that paracrine FGFs can exert FGF hormone-like metabolic activities has restored interest in these FGFs. The recent structural elucidation of the FGF cell surface signalling machinery and the formulation of a new threshold model for FGF signalling specificity have paved the way for therapeutically harnessing paracrine FGFs for the treatment of a range of metabolic diseases.

Hepatokines and their role in cardiohepatic interactions in heart failure

Heart failure is one of the leading causes of death and disease worldwide. It is a condition that affects multiple systems within the body. There is a large body of evidence supporting that the liver is a major organ involved in the pathogenesis of heart failure. Cardiac hepatopathy and cirrhotic cardiomyopathy are two conditions that are associated with poor clinical outcomes in patients with heart failure. Despite the extensive proposed explanations of the mechanisms entailing heart failure, there remains a gap in the role of proteins and metabolic regulators produced by hepatocytes and their effect on the development, progression, and prognosis of heart failure, including adverse cardiac remodeling, fibrosis, cardiac cachexia, and renal dysfunction associated with heart failure. The aim of this review is to identify the major hepatokines being studied (adropin, fetuin-A, fetuin-B, FGF-21, selenoprotein P and α1-microglobulin) as modulators of metabolic homeostasis and cardiac dysfunction in heart failure. Research suggests that these factors play a role in modulating oxidative stress, fibrosis, apoptosis, inflammatory responses, immune cell activation, mitochondrial dysfunction, and cellular migration. The exact role of each of these hepatokines is under on-going research and requires more investigations for future clinical use.

FGF21 Ameliorates Fibroblasts Activation and Systemic Sclerosis by Inhibiting CK2α/GLI2 Signaling Axis

Systemic sclerosis is a typical fibrotic disease of unknown etiology that is characterized by abnormal fibroblast activation and excessive deposition of extracellular matrix. Unfortunately, effective therapeutic approaches are lacking. FGF21 plays a key role in mediating a variety of biological activities. However, its specific function in systemic sclerosis is unclear. In this study, we found that the expression of FGF21 was significantly downregulated in fibrotic skin tissue and in TGF-β-stimulated fibroblasts. Furthermore, our studies demonstrated that treatment with recombinant FGF21 in the skin significantly alleviated bleomycin-induced and TBRI-activated fibrosis and inhibited the activation of fibroblasts, whereas skin fibrosis was exacerbated by deletion of FGF21. Mechanistically, FGF21 inhibits the activity of CK2α and promotes the degradation of GLI2. In conclusion, these results indicate that FGF21 attenuates skin fibrosis through the CK2α/GLI2 signaling pathway and therefore may be a potential therapeutic target for systemic sclerosis.

Functions of FGF21 and its role in cardiac hypertrophy

BACKGROUND

FGF21 is a stress-inducible hormone that operates in the autocrine or paracrine manner. Recent reports have revealed that FGF21 is highly expressed in cardiac hypertrophy to protect against heart injury and dysfunction. FGF21 is used to treat cardiac hypertrophy in mouse models. However, preclinical and clinical trials are restricted.

AIM OF REVIEW

This review mainly elucidates the diverse functions of FGF21 and explores the relationship between these functions and cardiac hypertrophy. It also discusses challenges and future perspectives in treating cardiac hypertrophy with FGF21.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review first illustrates the functions of FGF21, including energy metabolism, inflammation, oxidative stress, apoptosis, and autophagy. We also summarize vital functions and the underlying mechanisms through which FGF21 regulates the initiation and development of cardiac hypertrophy, connecting energy metabolism, inflammation, oxidative stress, apoptosis, and autophagy. Finally, we propose that FGF21 may be a potential therapeutic strategy for cardiac hypertrophy.

Fibroblast Growth Factor 20 Attenuates Colitis by Restoring Impaired Intestinal Epithelial Barrier Integrity and Modulating Macrophage Polarization via S100A9 in an NF-κB-Dependent Manner

BACKGROUND & AIMS

Exogenous recombinant fibroblast growth factor 20 (FGF20) protein has been proved to treat ulcerative colitis; however, its mechanism of action remains unclear. This study aimed to explore the role and mechanism of action of FGF20 in ulcerative colitis.

METHODS

Data from patients with ulcerative colitis were analyzed using the Gene Expression Omnibus dataset. A murine colitis model was established by administering 2% dextran sodium sulfate. FGF20 knockout mice and Adenoassociated viruses (AAV)-FGF20-treated mice were used to elucidate the specific mechanisms. Proteomic analysis was conducted to identify differentially expressed genes.

RESULTS

FGF20 levels were significantly elevated in the colonic tissues of subjects and mice with colitis. FGF20 deficiency exacerbated dextran sodium sulfate-induced colitis; in contrast, FGF20 replenishment alleviated colitis through 2 principal mechanisms: restoration of impaired intestinal epithelial barrier integrity, and inhibition of M1 macrophage polarization. Notably, S100A9 was identified as a pivotal downstream target of FGF20, which was further demonstrated by pharmacologic inhibition and overexpression experiments of S100A9 using paquinimod (a specific inhibitor of S100A9) and AAV-S100A9 in FGF20 knockout and AAV-FGF20 mice with colitis, respectively. Additionally, the nuclear factor-κB pathway was found to be involved in the process by which FGF20 regulates S100A9 to counteract colitis.

CONCLUSIONS

These results suggest that FGF20 acts as a negative regulator of S100A9 and nuclear factor-κB, thereby inhibiting M1 macrophage polarization and restoring intestinal epithelial barrier integrity in mice with dextran sodium sulfate-induced colitis. FGF20 may serve as a potential therapeutic target for the treatment of ulcerative colitis.

Sacubitril/Valsartan partially alleviates myocardial infarction injury by activating the FGF21 signaling pathway via PPARs

The recent discovery of clinically significant data, alongside novel physiological and pathological occurrences surrounding sacubitril/valsartan (Sac/Val) beyond its approved indications, necessitates an urgent reevaluation of its underlying mechanism of action. In the present investigation, we observed a substantial elevation in the serum levels of fibroblast growth factor 21 (FGF21) among patients with acute myocardial infarction (AMI) who were administered Sac/Val, compared to those who were not, utilizing ELISA-based measurements. Furthermore, through the utilization of a mouse model of myocardial infarction induced by ligation of the left anterior descending branch, we confirmed that FGF21 mediates the cardioprotective effect of Sac/Val, employing both loss-of-function and gain-of-function approaches. Molecular docking and SPR experiments validated that Sac/Val can regulate FGF21 via its interaction with PPARs, and verified the role of PPARs in mediating Sac/Val regulation of FGF21 by inhibiting PPARs. In conclusion, we found that Sac/Val can act as an agonist of FGF21, which provides a new idea for the development of FGF21 drugs, and FGF21 as a new target of Sac/Val to ameliorate myocardial infarction, which provides a basis for new indications for Sac/Val.

FGF21 protects against HFpEF by improving cardiac mitochondrial bioenergetics in mice

Fibroblast growth factor 21 (FGF21), a metabolic hormone with pleiotropic effects, is beneficial for various cardiac disorders. However, FGF21's role in heart failure with preserved ejection fraction (HFpEF) remains unclear. Here, we show that elevated circulating FGF21 levels are negatively associated with cardiac diastolic function in patients with HFpEF. Global or adipose FGF21 deficiency exacerbates cardiac diastolic dysfunction and damage in high-fat diet (HFD) plus N[w]-nitro-L-arginine methyl ester (L-NAME)-induced HFpEF mice, whereas these effects are notably reversed by FGF21 replenishment. Mechanistically, FGF21 enhances the production of adiponectin (APN), which in turn indirectly acts on cardiomyocytes, or FGF21 directly targets cardiomyocytes, to negatively regulate pyruvate dehydrogenase kinase 4 (PDK4) production by activating PI3K/AKT signals, then promoting mitochondrial bioenergetics. Additionally, APN deletion strikingly abrogates FGF21's protective effects against HFpEF, while genetic PDK4 inactivation markedly mitigates HFpEF in mice. Thus, FGF21 protects against HFpEF via fine-tuning the multiorgan crosstalk among the adipose, liver, and heart.

Fibroblast growth factor 21: a novel link in the development and treatment of metabolic disorders

In recent years, fibroblast growth factor 21 (FGF21) has garnered increasing attention as a metabolic regulator. It plays a role in the development of tissue insulin sensitivity, exerts beneficial effects on carbohydrate and lipid metabolism, and exhibits antihyperglycemic and antilipidemic properties. Elevated FGF21 levels have been observed in patients with type 2 diabetes, obesity, non-alcoholic fatty liver disease, and a range of other conditions. This may indicate either resistance to FGF21 or a compensatory response to metabolic stress. Evidence suggests that FGF21 can be considered both a marker of several metabolic disorders and a potential therapeutic agent for the treatment of significant societal health issues. Objective. The objective of this review is to summarize the data published to date in the literature, including meta-analyses, reviews, and original studies, focusing on the diagnostic and potential therapeutic role of FGF21 in metabolic disorders.

Circulating fibroblast growth factor 21 levels in gestational diabetes mellitus and preeclampsia: a systematic review and meta-analysis

BACKGROUND

The connection between fibroblast growth factor 21 (FGF21) and the likelihood of gestational diabetes mellitus (GDM) or preeclampsia (PE) has received more attention recently. Based on published articles, meta-analysis were conducted to explore the differences in FGF21 levels in GDM or PE compared to control groups.

METHODS

Articles published before April 5, 2024 were searched across four databases: PubMed, Web of Science, Embase, and Cochrane Library, and studies exploring the association of FGF21 levels and GDM or PE were collected. Additionally, ClinicalTrials.gov was also searched for completed and ongoing trials. (Prospero Registration CRD42024504738). The standardized mean differences (SMDs) and 95% confidence intervals (CIs) were utilized to determine FGF21 levels among different groups.

RESULTS

This analysis incorporated a total of 16 articles, with 714 GDM and 701 non-GDM in the control group. The GDM-affected pregnant women had greater levels of circulating FGF21 than the control group (SMD = 0.529, 95% CI: 0.168 ~ 0.890, p = 0.004). Moreover, the PE case group covered 120 while the control group contained 134. The findings indicated that pregnant women with PE had significantly greater levels of circulating FGF21 than healthy expectant mothers (SMD = 0.743, 95% CI: 0.527 ~ 0.958, p = 0.000).

CONCLUSIONS

Our study found that FGF21 has the potential to serve as a diagnostic marker for GDM or PE. However, due to the limited number of studies and the fact that most data were from the second and third trimesters of pregnancy, more large-scale prospective studies are needed to validate these conclusions, investigate the potential of FGF21 in enabling early diagnosis, and further examine the role of FGF21 in the development and progression of GDM/PE.

TRIAL REGISTRATION

Not applicable.

Maternal exercise represses FGF21 via SIRT1 to improve the phenotypic transformation of vascular smooth muscle in hypertensive offspring

Maternal exercise during pregnancy is widely recognized as an effective means of promoting cardiovascular health in offspring. Few studies have explored how maternal exercise impacts vascular function and phenotypic switching in hypertensive offspring, despite the known involvement of vascular structural and functional remodeling in hypertension pathogenesis. Research indicates a significant relationship between elevated blood pressure and fibroblast growth factor 21 (FGF21) levels. It remains unclear whether maternal exercise during pregnancy can improve vascular function in hypertensive offspring by regulating FGF21 and its underlying mechanisms. In this study, pregnant spontaneously hypertensive rats and Wistar-Kyoto rats were randomly assigned to either a sedentary or exercise group. The exercise group underwent weightless swimming exercise from gestation day 1 (GD1) to GD20. The aim was to investigate the epigenetic modifications mediated by histone deacetylase sirtuin 1 (SIRT1) during the fetal period and the phenotypic changes in the mesenteric arteries (MAs) of hypertensive offspring. We found that maternal exercise significantly improved vascular remodeling in hypertensive offspring. Specifically, maternal exercise upregulated SIRT1 expression, which led to decreased H3K9ac (histone H3 lysine 9 acetylation) in the promoter region of the FGF21 gene. This epigenetic modification resulted in the transcriptional downregulation of FGF21 in the MAs of hypertensive fetuses. These results suggest that maternal exercise may lower blood pressure in hypertensive offspring by regulating deacetylation of the FGF21 gene promoter region through SIRT1, thereby reversing phenotypic switching and vascular structural remodeling.

FGF21 attenuates salt-sensitive hypertension via regulating HNF4α/ACE2 axis in the hypothalamic paraventricular nucleus of mice

BACKGROUND

Fibroblast growth factor 21 (FGF21) has a protective effect against cardiovascular disease. However, the role of FGF21 in hypertension remains elusive.

METHODS

Ten-week-old male C57BL/6 mice were randomly divided into normal-salt (NS) group, NS+FGF21 group, deoxycorticosterone acetate-salt (DOCA) group and DOCA+FGF21 group. The mice in NS group underwent uninephrectomy without receiving DOCA and 1% NaCl and the mice in DOCA group were subjected to uninephrectomy and DOCA-salt (DOCA and 1% NaCl) treatment for 6 weeks. At the same time, the mice were infused with vehicle (artificial cerebrospinal fluid, aCSF) or FGF21 (1 mg/kg) into the bilateral paraventricular nucleus (PVN) of mice.

RESULTS

Here, we showed that FGF21 treatment lowered DOCA salt-induced inflammation and oxidative stress in the PVN, which reduced sympathetic nerve activity and hypertension. Mechanistically, FGF21 treatment decreased the expression of HNF4α and inhibited the binding activity of HNF4α to the promoter region of ACE2 in the PVN of DOCA salt-treated mice, which further up-regulated ACE2/Ang (1-7) signals in the PVN. In addition, ACE2 deficiency abolished the protective effect of FGF21 in DOCA salt-treated mice, suggesting that FGF21-mediated antihypertensive effect was dependent on ACE2.

CONCLUSIONS

The results demonstrate that FGF21 protects against salt-sensitive hypertension via regulating HNF4α/ACE2/Ang (1-7) axis in the PVN of DOCA salt-treated mice via multi-organ crosstalk between liver, brain and blood vessels.

Insights into the role of FGF21 in coronary heart disease

Coronary heart disease (CHD) remains a leading cause of global mortality, with an alarming increase in its incidence among the younger population in recent years. This has amplified the need for early diagnostic markers and advances in therapeutic strategies to improve patient outcomes. Fibroblast growth factor 21 (FGF21), an endocrine hormone crucial for the regulation of metabolic homeostasis, has garnered significant attention over the past decade, owing to its role in cardiovascular health. FGF21 exerts cardioprotective effects through various mechanisms, including regulation of myocardial energy metabolism, prevention of cardiac cell death, suppression of inflammation, and reduction of oxidative stress in the heart. Given these properties, FGF21 shows considerable promise as a pharmacological agent for the management of CHD. Moreover, it has emerged as a promising biomarker for the diagnosis and prognostic assessment of CHD. This review aims to clarify the molecular mechanisms underlying the favorable effects of FGF21 on CHD and its related risk factors, thereby providing valuable insights for future research on the role of FGF21 in CHD management.

Fibroblast growth factor 21 alleviates acetaminophen induced acute liver injury by activating Sirt1 mediated autophagy

BACKGROUND AND AIMS

Acetaminophen (APAP) is the main cause of acute liver injury (ALI) in the Western. Our previous study has shown that fenofibrate activated hepatic expression of fibroblast growth factor 21 (FGF21) can protect the liver form APAP injuries by promoting autophagy. However, the underlying mechanism involved in FGF21-mediated autophagy remains unsolved.

METHODS

The ALI mice model was established by intraperitoneal injection of APAP. To investigate the influence of FGF21 on autophagy and Sirt1 expression in APAP-induced ALI, FGF21 knockout (FGF21KO) mice and exogenously supplemented mouse recombinant FGF21 protein were used. In addition, primary isolated hepatocytes and the Sirt1 inhibitor EX527 were used to observe whether FGF21 activated autophagy in APAP injury is regulated by Sirt1 at the cellular level.

RESULTS

FGF21, Sirt1, and autophagy levels increased in mice with acute liver injury (ALI) and in primary cultured hepatocytes. Deletion of the FGF21 gene exacerbated APAP-induced liver necrosis and oxidative stress, and decreased mitochondrial potential. It also reduced the mRNA and protein levels of autophagy-related proteins such as Sirt1, LC3-II, and p62, as well as the number of autophagosomes. Replenishment of FGF21 reversed these processes. In addition, EX527 partially counteracted the protective effect of FGF21 by worsening oxidative damage, mitochondrial damage, and reducing autophagy in primary liver cells treated with APAP.

CONCLUSION

FGF21 increases autophagy by upregulating Sirt1 to alleviate APAP-induced injuries.

ACE2 deficiency inhibits thoracic aortic dissection by enhancing SIRT3 mediated inhibition of inflammation and VSCMs phenotypic switch

BACKGROUND

Thoracic aortic dissection (TAD) is an irreversible cardiovascular disorder with high mortality and morbidity. However, the molecular mechanisms remain elusive. Thus, identifying an effective therapeutic target to prevent TAD is especially critical. The purpose of this study is to elucidate the potential mechanism of inflammation and vascular smooth muscle cell (VSMCs) phenotypic switch in β-aminopropionitrile fumarate (BAPN)-induced TAD.

METHODS

A mouse model of TAD induced by BAPN and IL-1β -stimulated HVSMCs in vivo and in vitro models, respectively. ACE2 Knockdown mice treated with BAPN or without, and the TAD mouse model was treated with or without AAV-ACE2. Transthoracic ultrasound was conducted for assessment the maximum internal diameter of the thoracic aorta arch. RNA sequencing analysis was performed to recapitulate transcriptome profile changes. Western blot were used to detect the expression of MMP2, MMP9, ACE2, SIRT3, OPN, SM22α and other inflammatory markers. The circulating levels of ACE2 was measured by ELISA assay. Histological changes of thoracic aorta tissues were assessed by H&E, EVG and IHC analysis.

RESULTS

We found that circulating levels of and the protein levels of ACE2 were increased in the TAD mouse model and in patients with TAD. For further evidence, ACE2 deficiency decelerated the formation of TAD. However, overexpression of ACE2 aggravated BAPN-induced aortic injury and VSMCs phenotypic switch via lowered SIRT3 expression and elevated inflammatory cytokine expression.

CONCLUSION

ACE2 deficiency prevented the development of TAD by inhibiting inflammation and VSMCs phenotypic switch in a SIRT3-dependent manner, suggesting that the ACE2/SIRT3 signaling pathway played a pivotal role in the pathological process of TAD and might be a potential therapeutical target.

Resolution of inflammation, an active process to restore the immune microenvironment balance: A novel drug target for treating arterial hypertension

The resolution of inflammation, the other side of the inflammatory response, is defined as an active and highly coordinated process that promotes the restoration of immune microenvironment balance and tissue repair. Inflammation resolution involves several key processes, including dampening proinflammatory signaling, specialized proresolving lipid mediator (SPM) production, nonlipid proresolving mediator production, efferocytosis and regulatory T-cell (Treg) induction. In recent years, increasing attention has been given to the effects of inflammation resolution on hypertension. Furthermore, our previous studies reported the antihypertensive effects of SPMs. Therefore, in this review, we aim to summarize and discuss the detailed association between arterial hypertension and inflammation resolution. Additional, the association between gut microbe-mediated immune and hypertension is discussed. This findings suggested that accelerating the resolution of inflammation can have beneficial effects on hypertension and its related organ damage. Exploring novel drug targets by focusing on various pathways involved in accelerating inflammation resolution will contribute to the treatment and control of hypertensive diseases in the future.

Endothelial deubiquinatase YOD1 mediates Ang II-induced vascular endothelial-mesenchymal transition and remodeling by regulating β-catenin

Hypertension is a prominent contributor to vascular injury. Deubiquinatase has been implicated in the regulation of hypertension-induced vascular injury. In the present study we investigated the specific role of deubiquinatase YOD1 in hypertension-induced vascular injury. Vascular endothelial endothelial-mesenchymal transition (EndMT) was induced in male WT and YOD1-/- mice by administration of Ang II (1 μg/kg per minute) via osmotic pump for four weeks. We showed a significantly increased expression of YOD1 in mouse vascular endothelial cells upon Ang II stimulation. Knockout of YOD1 resulted in a notable reduction in EndMT in vascular endothelial cells of Ang II-treated mouse; a similar result was observed in Ang II-treated human umbilical vein endothelial cells (HUVECs). We then conducted LC-MS/MS and co-immunoprecipitation (Co-IP) analyses to verify the binding between YOD1 and EndMT-related proteins, and found that YOD1 directly bound to β-catenin in HUVECs via its ovarian tumor-associated protease (OTU) domain, and histidine at 262 performing deubiquitination to maintain β-catenin protein stability by removing the K48 ubiquitin chain from β-catenin and preventing its proteasome degradation, thereby promoting EndMT of vascular endothelial cells. Oral administration of β-catenin inhibitor MSAB (20 mg/kg, every other day for four weeks) eliminated the protective effect of YOD1 deletion on vascular endothelial injury. In conclusion, we demonstrate a new YOD1-β-catenin axis in regulating Ang II-induced vascular endothelial injury and reveal YOD1 as a deubiquitinating enzyme for β-catenin, suggesting that targeting YOD1 holds promise as a potential therapeutic strategy for treating β-catenin-mediated vascular diseases.

Transitions in chromatin conformation shaped by fatty acids and the circadian clock underlie hepatic transcriptional reorganization in obese mice

The circadian clock system coordinates metabolic, physiological, and behavioral functions across a 24-h cycle, crucial for adapting to environmental changes. Disruptions in circadian rhythms contribute to major metabolic pathologies like obesity and Type 2 diabetes. Understanding the regulatory mechanisms governing circadian control is vital for identifying therapeutic targets. It is well characterized that chromatin remodeling and 3D structure at genome regulatory elements contributes to circadian transcriptional cycles; yet the impact of rhythmic chromatin topology in metabolic disease is largely unexplored. In this study, we explore how the spatial configuration of the genome adapts to diet, rewiring circadian transcription and contributing to dysfunctional metabolism. We describe daily fluctuations in chromatin contacts between distal regulatory elements of metabolic control genes in livers from lean and obese mice and identify specific lipid-responsive regions recruiting the clock molecular machinery. Interestingly, under high-fat feeding, a distinct interactome for the clock-controlled gene Dbp strategically promotes the expression of distal metabolic genes including Fgf21. Alongside, new chromatin loops between regulatory elements from genes involved in lipid metabolism control contribute to their transcriptional activation. These enhancers are responsive to lipids through CEBPβ, counteracting the circadian repressor REVERBa. Our findings highlight the intricate coupling of circadian gene expression to a dynamic nuclear environment under high-fat feeding, supporting a temporally regulated program of gene expression and transcriptional adaptation to diet.

A study on the early metabolic effects of salt and fructose consumption: the protective role of water

Increasing serum osmolality has recently been linked with acute stress responses, which over time can lead to increased risk for obesity, hypertension, and other chronic diseases. Salt and fructose are two major stimuli that can induce acute changes in serum osmolality. Here we investigate the early metabolic effects of sodium and fructose consumption and determine whether the effects of sodium or fructose loading can be mitigated by blocking the change in osmolality with hydration. Forty-four healthy subjects without disease and medication were recruited into four groups. After overnight fasting, subjects in Group 1 drank 500 mL of salty soup, while those in Group 2 drank 500 mL of soup without salt for 15 min. Subjects in Group 3 drank 500 mL of 100% apple juice in 5 min, while subjects in Group 4 drank 500 mL of 100% apple juice and 500 mL of water in 5 min. Blood pressure (BP), plasma sodium, and glucose levels were measured every 15 min in the first 2 h. Serum and urine osmolarity, serum uric acid, cortisol, fibroblast growth factor 21 (FGF21), aldosterone, adrenocorticotropic hormone (ACTH) level, and plasma renin activity (PRA) were measured at the baseline and 2 h. Both acute intake of salt or fructose increased serum osmolality (maximum ∼4 mOsm/L peaking at 75 min) associated with a rise in systolic and diastolic BP, PRA, aldosterone, ACTH, cortisol, plasma glucose, uric acid, and FGF21. Salt tended to cause greater activation of the renin-angiotensin-system (RAS), while fructose caused a greater rise in glucose and FGF21. In both cases, hydration could prevent the osmolality and largely block the acute stress response. Acute changes in serum osmolality can induce remarkable activation of the ACTH-cortisol, RAS, glucose metabolism, and uric acid axis that is responsive to hydration. In addition to classic dehydration, salt, and fructose-containing sugars can activate these responses. Staying well hydrated may provide benefits despite exposure to sugar and salt. More studies are needed to investigate whether hydration can block the chronic effects of sugar and salt on disease.

Correlation of circulating fibroblast growth factor 21 levels with inflammatory factors and the degree of coronary artery stenosis in patients with acute myocardial infarction

BACKGROUND

Fibroblast growth factor 21 (FGF21) is a secreted protein that plays an important role in atherosclerosis and pathological cardiac remodeling. However, the correlation between FGF21 and the degree of coronary artery stenosis and its potential role in acute myocardial infarction (AMI) remain unclear. We examined whether changes in FGF21 levels in AMI correlate with the degree of coronary artery stenosis and the levels of inflammatory factors, and preliminarily investigated the effects of FGF21 on inflammatory factor levels and myocardial injury in rats with AMI.

METHODS

Serum levels of FGF21 and inflammatory factors in the AMI group and control group were measured, and the correlation between FGF21 and clinical indicators and inflammatory factors was analyzed. The effects of FGF21 on cardiac function and inflammatory response were evaluated through echocardiography and measurement of inflammatory factors.

RESULTS

Multivariate logistic regression analysis showed that neutrophil percentage (NEUT%, odds ratio [OR]: 1.232; 95 % confidence interval [CI]: 1.028-1.477; p = 0.024) and FGF21 levels (OR: 2.063; 95 % CI: 1.187-3.586; p = 0.01) had independent effects on AMI. Spearman's rank correlation test showed that FGF21 levels were positively correlated with leukocyte count, NEUT%, neutrophil count, neutrophil to lymphocyte ratio, C-reactive protein, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1) and Gensini scores (p < 0.01), but negatively correlated with lymphocyte count (p < 0.01). FGF21 levels in myocardial tissues and serum levels of FGF21, IL-6, TNF-a, and MCP-1 were significantly higher in AMI rats than in the sham-operated group (p < 0.01). After overexpression of FGF21, serum levels of IL-6, TNF-a, and MCP-1 in rats were significantly decreased (p < 0.01), and cardiac function improved significantly.

CONCLUSIONS

FGF21 levels were independently associated with AMI and may be related to the severity of coronary artery stenosis. Overexpression of FGF21 reduced serum inflammatory factor levels and improved cardiac function in AMI rats.

Integrative analyses of whole-transcriptome sequencing reveals CeRNA regulatory network in pulmonary hypertension treated with FGF21

Noncoding RNAs have been shown to play essential roles in hypoxic pulmonary hypertension (HPH). Our preliminary data showed that HPH is attenuated by fibroblast growth factor 21 (FGF21) administration. Therefore, we further investigated the whole transcriptome RNA expression patterns and interactions in a mice HPH model treated with FGF21. By whole-transcriptome sequencing, differentially expressed mRNAs, miRNAs, lncRNAs, and circRNAs were successfully identified in normoxia (Nx) vs. hypoxia (Hx) and Hx vs. hypoxia + FGF21 (Hx + F21). Differentially expressed mRNAs, miRNAs, lncRNAs, and circRNAs regulated by hypoxia and FGF21 were selected through intersection analysis. Based on prediction databases and sequencing data, differentially co-expressed mRNAs, miRNAs, lncRNAs, and circRNAs were further screened, followed by functional enrichment analysis. MAPK signaling pathway and epigenetic modification were enriched and may play fundamental roles in the therapeutic effects of FGF21. The ceRNA regulatory network of lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA was constructed with miR-7a-5p, miR-449c-5p, miR-676-3p and miR-674-3p as the core. In addition, quantitative real-time PCR experiments were employed to verify the whole-transcriptome sequencing data. The results of luciferase reporter assays highlighted the relationship between miR-449c-5p and XR_878320.1, miR-449c-5p and Stab2, miR-449c-5p and circ_mtcp1, which suggesting that miR-449c-5p may be a key regulator of FGF21 in the treatment of PH. Taken together, this study provides potential biomarkers, pathways, and ceRNA regulatory networks in HPH treated with FGF21 and will provide an experimental basis for the clinical application of FGF21 in PH.

Adipose c-Jun NH2-terminal kinase promotes angiotensin II-induced and deoxycorticosterone acetate salt-induced hypertension and vascular dysfunction by inhibition of adiponectin production and activation of SGK1 in mice

BACKGROUND

Adipose c-Jun NH2-terminal kinase 1/2 (JNK1/2) is a central mediator involved in the development of obesity and its complications. However, the roles of adipose JNK1/2 in hypertension remain elusive. Here we explored the role of adipose JNK1/2 in hypertension.

METHODS AND RESULTS

The roles of adipose JNK1/2 in hypertension were investigated by evaluating the impact of adipose JNK1/2 inactivation in both angiotensin II (Ang II)-induced and deoxycorticosterone acetate (DOCA) salt-induced hypertensive mice. Specific inactivation of JNK1/2 in adipocytes significantly alleviates Ang II-induced and DOCA salt-induced hypertension and target organ damage in mice. Interestingly, such beneficial effects are also observed in hypertensive mice after oral administration of JNK1/2 inhibitor SP600125. Mechanistically, adipose JNK1/2 acts on adipocytes to reduce the production of adiponectin (APN), then leads to promote serum and glucocorticoid-regulated kinase 1 (SGK1) phosphorylation and increases epithelial Na + channel α-subunit (ENaCα) expression in both renal cells and adipocytes, respectively, finally exacerbates Na + retention. In addition, chronic treatment of recombinant mouse APN significantly augments the beneficial effects of adipose JNK1/2 inactivation in DOCA salt-induced hypertension. By contrast, the blood pressure-lowering effects of adipose JNK1/2 inactivation are abrogated by adenovirus-mediated SGK1 overexpression in Ang II -treated adipose JNK1/2 inactivation mice.

CONCLUSION

Adipose JNK1/2 promotes hypertension and targets organ impairment via fine-tuning the multiorgan crosstalk among adipose tissue, kidney, and blood vessels.

FGF7 enhances the expression of ACE2 in human islet organoids aggravating SARS-CoV-2 infection

The angiotensin-converting enzyme 2 (ACE2) is a primary cell surface viral binding receptor for SARS-CoV-2, so finding new regulatory molecules to modulate ACE2 expression levels is a promising strategy against COVID-19. In the current study, we utilized islet organoids derived from human embryonic stem cells (hESCs), animal models and COVID-19 patients to discover that fibroblast growth factor 7 (FGF7) enhances ACE2 expression within the islets, facilitating SARS-CoV-2 infection and resulting in impaired insulin secretion. Using hESC-derived islet organoids, we demonstrated that FGF7 interacts with FGF receptor 2 (FGFR2) and FGFR1 to upregulate ACE2 expression predominantly in β cells. This upregulation increases both insulin secretion and susceptibility of β cells to SARS-CoV-2 infection. Inhibiting FGFR counteracts the FGF7-induced ACE2 upregulation, subsequently reducing viral infection and replication in the islets. Furthermore, retrospective clinical data revealed that diabetic patients with severe COVID-19 symptoms exhibited elevated serum FGF7 levels compared to those with mild symptoms. Finally, animal experiments indicated that SARS-CoV-2 infection increased pancreatic FGF7 levels, resulting in a reduction of insulin concentrations in situ. Taken together, our research offers a potential regulatory strategy for ACE2 by controlling FGF7, thereby protecting islets from SARS-CoV-2 infection and preventing the progression of diabetes in the context of COVID-19.

Hormone-based pharmacotherapy for metabolic dysfunction-associated fatty liver disease

Metabolic dysfunction-associated fatty liver disease (MAFLD) has reached epidemic proportions globally in parallel to the rising prevalence of obesity. Despite its significant burden, there is no approved pharmacotherapy specifically tailored for this disease. Many potential drug candidates for MAFLD have encountered setbacks in clinical trials, due to safety concerns or/and insufficient therapeutic efficacy. Nonetheless, several investigational drugs that mimic the actions of endogenous metabolic hormones, including thyroid hormone receptor β (THRβ) agonists, fibroblast growth factor 21 (FGF21) analogues, and glucagon-like peptide-1 receptor agonists (GLP-1RAs), showed promising therapeutic efficacy and excellent safety profiles. Among them, resmetirom, a liver-targeted THRβ-selective agonist, has met the primary outcomes in alleviation of metabolic dysfunction-associated steatohepatitis (MASH), the advanced form of MAFLD, and liver fibrosis in phase-3 clinical trials. These hormone-based pharmacotherapies not only exhibit varied degrees of therapeutic efficacy in mitigating hepatic steatosis, inflammation and fibrosis, but also improve metabolic profiles. Furthermore, these three hormonal agonists/analogues act in a complementary manner to exert their pharmacological effects, suggesting their combined therapies may yield synergistic therapeutic benefits. Further in-depth studies on the intricate interplay among these metabolic hormones are imperative for the development of more efficacious combination therapies, enabling precision management of MAFLD and its associated comorbidities.

One Endothelium-Targeted Combined Nucleic Acid Delivery System for Myocardial Infarction Therapy

Acute myocardial infarction (MI) and ischemic heart disease are the leading causes of heart failure and mortality. Currently, research on MI treatment is focused on angiogenic and anti-inflammatory therapies. Although endothelial cells (ECs) are critical for triggering inflammation and angiogenesis, no approach has targeted them for the treatment of MI. In this study, we proposed a nonviral combined nucleic acid delivery system consisting of an EC-specific polycation (CRPPR-grafted ethanolamine-modified poly(glycidyl methacrylate), CPC) that can efficiently codeliver siR-ICAM1 and pCXCL12 for the treatment of MI. Animals treated with the combination therapy exhibited better cardiac function than those treated with each nucleic acid alone. In particular, the combination therapy of CPC/siR-ICAM1 and CPC/pCXCL12 significantly improved cardiac systolic function, anti-inflammatory responses, and angiogenesis compared to the control group. In conclusion, CPC-based combined gene delivery systems show impressive performance in the treatment of MI and provide a programmed strategy for the development of codelivery systems for various EC-related diseases.

Mechanisms of inflammation modulation by different immune cells in hypertensive nephropathy

Hypertensive nephropathy (HTN) is the second leading cause of end-stage renal disease (ESRD) and a chronic inflammatory disease. Persistent hypertension leads to lesions of intrarenal arterioles and arterioles, luminal stenosis, secondary ischemic renal parenchymal damage, and glomerulosclerosis, tubular atrophy, and interstitial fibrosis. Studying the pathogenesis of hypertensive nephropathy is a prerequisite for diagnosis and treatment. The main cause of HTN is poor long-term blood pressure control, but kidney damage is often accompanied by the occurrence of immune inflammation. Some studies have found that the activation of innate immunity, inflammation and acquired immunity is closely related to the pathogenesis of HTN, which can cause damage and dysfunction of target organs. There are more articles on the mechanism of diabetic nephropathy, while there are fewer studies related to immunity in hypertensive nephropathy. This article reviews the mechanisms by which several different immune cells and inflammatory cytokines regulate blood pressure and renal damage in HTN. It mainly focuses on immune cells, cytokines, and chemokines and inhibitors. However, further comprehensive and large-scale studies are needed to determine the role of these markers and provide effective protocols for clinical intervention and treatment.

Myeloid ACE2 protects against septic hypotension and vascular dysfunction through Ang-(1-7)-Mas-mediated macrophage polarization

Angiotensin converting enzyme 2 (ACE2) is a new identified member of the renin-angiotensin-aldosterone system (RAAS) that cleaves angiotensin II (Ang II) to Ang (1-7), which exerts anti-inflammatory and antioxidative activities via binding with Mas receptor (MasR). However, the functional role of ACE2 in sepsis-related hypotension remains unknown. Our results indicated that sepsis significantly reduced blood pressure and led to disruption between ACE-Ang II and ACE2-Ang (1-7) balance. ACE2 knock-in mice exhibited improved sepsis-induced mortality, hypotension and vascular dysfunction, while ACE2 knockout mice exhibited the opposite effects. Bone marrow transplantation and in vitro experiments confirmed that myeloid ACE2 exerted a protective role by suppressing oxidative stress, NO production and macrophage polarization via the Ang (1-7)-MasR-NF-κB and STAT1 pathways. Thus, ACE2 on myeloid cells could protect against sepsis-mediated hypotension and vascular dysfunction, and upregulating ACE2 may represent a promising therapeutic option for septic patients with hypotension.

Fibroblast Growth Factor 21 Relieves Lipopolysaccharide-Induced Acute Lung Injury by Suppressing JAK2/STAT3 Signaling Pathway

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a life-threatening disease without an effective drug at present. Fibroblast growth factor 21 (FGF21) was reported to be protective against inflammation in metabolic disease in recent studies. However, the role of FGF21 in ALI has been rarely investigated. In this study, it was found that the expression of FGF21 was markedly increased in lung tissue under lipopolysaccharide (LPS) stimulation in vivo, whereas it was decreased in lung epithelial cells under LPS stimulation in vitro. Therefore, our research aimed to elucidate the potential role of FGF21 in LPS-induced ALI and to detect possible underlying mechanisms. The results revealed that the deficiency of FGF21 aggravated pathological damage, inflammatory infiltration, and pulmonary function in LPS-induced ALI, while exogenous administration of FGF21 improved these manifestations. Moreover, through RNA sequencing and enrichment analysis, it was unveiled that FGF21 might play a protective role in LPS-induced ALI via JAK2/STAT3 signaling pathway. The therapeutic effect of FGF21 was weakened after additional usage of JAK2 activator in vivo. Further investigation revealed that FGF21 significantly inhibited STAT3 phosphorylation and impaired the nuclear translocation of STAT3 in vitro. In addition, the aggravation of inflammation caused by silencing FGF21 can be alleviated by JAK2 inhibitor in vitro. Collectively, these findings unveil a potent protective effect of FGF21 against LPS-induced ALI by inhibiting the JAK2/STAT3 pathway, implying that FGF21 might be a novel and effective therapy for ALI.

Dynamics of Endothelial Cell Generation and Turnover in Arteries During Homeostasis and Diseases

BACKGROUND

Endothelial cell (EC) generation and turnover by self-proliferation contributes to vascular repair and regeneration. The ability to accurately measure the dynamics of EC generation would advance our understanding of cellular mechanisms of vascular homeostasis and diseases. However, it is currently challenging to evaluate the dynamics of EC generation in large vessels such as arteries because of their infrequent proliferation.

METHODS

By using dual recombination systems based on Cre-loxP and Dre-rox, we developed a genetic system for temporally seamless recording of EC proliferation in vivo. We combined genetic recording of EC proliferation with single-cell RNA sequencing and gene knockout to uncover cellular and molecular mechanisms underlying EC generation in arteries during homeostasis and disease.

RESULTS

Genetic proliferation tracing reveals that ≈3% of aortic ECs undergo proliferation per month in adult mice during homeostasis. The orientation of aortic EC division is generally parallel to blood flow in the aorta, which is regulated by the mechanosensing protein Piezo1. Single-cell RNA sequencing analysis reveals 4 heterogeneous aortic EC subpopulations with distinct proliferative activity. EC cluster 1 exhibits transit-amplifying cell features with preferential proliferative capacity and enriched expression of stem cell markers such as Sca1 and Sox18. EC proliferation increases in hypertension but decreases in type 2 diabetes, coinciding with changes in the extent of EC cluster 1 proliferation. Combined gene knockout and proliferation tracing reveals that Hippo/vascular endothelial growth factor receptor 2 signaling pathways regulate EC proliferation in large vessels.

CONCLUSIONS

Genetic proliferation tracing quantitatively delineates the dynamics of EC generation and turnover, as well as EC division orientation, in large vessels during homeostasis and disease. An EC subpopulation in the aorta exhibits more robust cell proliferation during homeostasis and type 2 diabetes, identifying it as a potential therapeutic target for vascular repair and regeneration.

ATF3 coordinates the survival and proliferation of cardiac macrophages and protects against ischemia-reperfusion injury

Cardiac resident MerTK+ macrophages exert multiple protective roles after ischemic injury; however, the mechanisms regulating their fate are not fully understood. In the present study, we show that the GAS6-inducible transcription factor, activating transcription factor 3 (ATF3), prevents apoptosis of MerTK+ macrophages after ischemia-reperfusion (IR) injury by repressing the transcription of multiple genes involved in type I interferon expression (Ifih1 and Ifnb1) and apoptosis (Apaf1). Mice lacking ATF3 in cardiac macrophages or myeloid cells showed excessive loss of MerTK+ cardiac macrophages, poor angiogenesis and worse heart dysfunction after IR, which were rescued by the transfer of MerTK+ cardiac macrophages. GAS6 administration improved cardiac repair in an ATF3-dependent manner. Finally, we showed a negative association of GAS6 and ATF3 expression with the risk of major adverse cardiac events in patients with ischemic heart disease. These results indicate that the GAS6-ATF3 axis has a protective role against IR injury by regulating MerTK+ cardiac macrophage survival and/or proliferation.

The Counteracting Effects of Ang II and Ang-(1-7) on the Function andGrowth of Insulin-secreting NIT-1 Cells

INTRODUCTION

China now has the highest number of diabetes in the world. Angiotensin II (Ang II) causes insulin resistance by acting on the insulin signaling pathway of peripheral target tissues. However, its effect on islet β-cells remains unclear. The possible role of Angiotensin-( 1-7) [Ang-(1-7)] as an antagonist to the effects of Ang II and in treating diabetes needs to be elucidated.

OBJECTIVES

To assess the effects of Ang II and Ang-(1-7) on the function and growth of islet β cell line NIT-1, which is derived from the islets of non-obese diabetic/large T-antigen (NOD/LT) mice with insulinoma.

METHODS

NIT-1 cells were treated with Ang II, Ang-(1-7) and their respective receptor antagonists. The impact on cell function and growth was then evaluated.

RESULTS

Ang II significantly reduced insulin-stimulated IR-β-Tyr and Akt-Ser; while Ang-(1-7), saralasin (an Ang II receptor antagonist), and diphenyleneiodonium [DPI, a nicotinamide adenine dinucleotide phosphate oxidase (NOX) antagonist] reversed the inhibiting effect. Conversely, Ang II significantly increased insulin-stimulated intracellular H2O2 and P47 phox, while saralasin and DPI reverted the effect. Furthermore, Ang-(1-7) reduced the elevated concentrations of ROS and MDA while increasing the proliferation rate that was reduced by high glucose, all of which were reversed by A-779, an antagonist of the Mas receptor (MasR).

CONCLUSION

Angiotensin II poses a negative regulatory effect on insulin signal transduction, increases oxidative stress, and may inhibit the transcription of insulin genes stimulated by insulin in NIT-1 cells. Meanwhile, angiotensin-(1-7) blocked these effects via MasR. These results corroborate the rising potential of the renin-angiotensin system (RAS) in treating diabetes.

Interorgan communication with the liver: novel mechanisms and therapeutic targets

The liver is a multifunctional organ that plays crucial roles in numerous physiological processes, such as production of bile and proteins for blood plasma, regulation of blood levels of amino acids, processing of hemoglobin, clearance of metabolic waste, maintenance of glucose, etc. Therefore, the liver is essential for the homeostasis of organisms. With the development of research on the liver, there is growing concern about its effect on immune cells of innate and adaptive immunity. For example, the liver regulates the proliferation, differentiation, and effector functions of immune cells through various secreted proteins (also known as "hepatokines"). As a result, the liver is identified as an important regulator of the immune system. Furthermore, many diseases resulting from immune disorders are thought to be related to the dysfunction of the liver, including systemic lupus erythematosus, multiple sclerosis, and heart failure. Thus, the liver plays a role in remote immune regulation and is intricately linked with systemic immunity. This review provides a comprehensive overview of the liver remote regulation of the body's innate and adaptive immunity regarding to main areas: immune-related molecules secreted by the liver and the liver-resident cells. Additionally, we assessed the influence of the liver on various facets of systemic immune-related diseases, offering insights into the clinical application of target therapies for liver immune regulation, as well as future developmental trends.

Increased circulating FGF21 level predicts the burden of metabolic demands and risk of vascular diseases in adults with type 2 diabetes

OBJECTIVES

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by chronic hyperglycemia and metabolic stress, involved in the stepwise development of cardiovascular complications. Fibroblast growth factor 21 (FGF21) is a novel hepatokine involved in regulating glucose and lipid metabolism, and has been linked to the prediction, treatment, and improvement of prognosis in multiple cardiovascular diseases (CVDs). The aim of this study is to explore the relationship between FGF21 levels and vascular diseases (VDs) including carotid atherosclerosis (CAS) and hypertension (HP) in patients with T2DM.

METHODS

Baseline serum FGF21 was determined in a cross-sectional study of 701 patients with T2DM and 258 healthy control.

RESULTS

The morbidity of CAS was increased in T2DM patients with HP as compared with those without (p < 0.001). The average serum FGF21 level of healthy was [123.9 (67.2-219.3)]. Baseline FGF21 was significantly higher in those who developed CAS or HP than in those who did not [305.9 (177.2-508.4) vs. 197.2 (129.7-308.3) pg/mL, p < 0.001]. In addition, an elevated serum FGF21 was observed in T2DM patients with HP and CAS than that of T2DM patients with CAS or HP [550.5 (312.6-711.3) vs. 305.9 pg/mL, p < 0.001]. Serum FGF21 levels were positively correlated with body mass index and carotid intima media thicknes (p < 0.05), the association remained significant after adjusting for age and T2DM duration. Furthermore, the multinomial logistic regression showed that serum FGF21 was independently associated with CAS and HP in patients with T2DM after adjustment for demographic and traditional VDs risk factors (p < 0.001).

CONCLUSIONS

Baseline FGF21 is elevated in VDs during diabetes, changes of serum FGF21 levels were appropriately matched to metabolic stress. FGF21can be used as an independent predictor for diagnosing VDs and predicting prognosis.

MAPL loss dysregulates bile and liver metabolism in mice

Mitochondrial and peroxisomal anchored protein ligase (MAPL) is a dual ubiquitin and small ubiquitin-like modifier (SUMO) ligase with roles in mitochondrial quality control, cell death and inflammation in cultured cells. Here, we show that MAPL function in the organismal context converges on metabolic control, as knockout mice are viable, insulin-sensitive, and protected from diet-induced obesity. MAPL loss leads to liver-specific activation of the integrated stress response, inducing secretion of stress hormone FGF21. MAPL knockout mice develop fully penetrant spontaneous hepatocellular carcinoma. Mechanistically, the peroxisomal bile acid transporter ABCD3 is a primary MAPL interacting partner and SUMOylated in a MAPL-dependent manner. MAPL knockout leads to increased bile acid production coupled with defective regulatory feedback in liver in vivo and in isolated primary hepatocytes, suggesting cell-autonomous function. Together, our findings establish MAPL function as a regulator of bile acid synthesis whose loss leads to the disruption of bile acid feedback mechanisms. The consequences of MAPL loss in liver, along with evidence of tumor suppression through regulation of cell survival pathways, ultimately lead to hepatocellular carcinogenesis.

FGF21 protects against doxorubicin-induced cardiotoxicity by inhibiting connexin 43 ubiquitination

BACKGROUND

Fibroblast growth factor 21 (FGF21) regulates glycolipid metabolism and insulin homeostasis and acts as a cardioprotective factor by protecting against myocardial ischemia/reperfusion injury, hypertension, and vascular dysfunction. FGF21 has been reported to prevent Doxorubicin (Dox)-induced cardiotoxicity, and the related signaling pathway is worthy of further study. Connexin43 (Cx43) protein was reduced by Dox treatment, especially low phosphorylated form of Cx43. Thus the aim of study is to explore the protection effect of FGF21 on Dox induced cardiotoxicity by improving the expression of Cx43 and the involved signaling pathway.

METHODS AND RESULTS

FGF21 inhibited apoptosis in Dox-treated mice and cardiomyocytes. FGF21 increased the levels of connexin43 phosphorylated at serine (S) 282 (p-Cx43 S282) and total Cx43 to inhibit Dox-induced apoptosis. By RNA sequencing, we found that deubiquitinase monocyte chemoattractant protein-induced protein 1 (MCPIP1) expression was increased by FGF21. We further found that FGF21 induced the phosphorylation of fibroblast growth factor receptor 1 (FGFR1), extracellular signal-regulated kinase 1 and 2 (Erk1/2), and Elk. Phosphorylated Elk translocated to the nucleus and increased the expression of MCPIP1. Then, MCPIP1 bound neural precursor cell expressed developmentally downregulated protein 4 (Nedd4), an E3 ubiquitination ligase, as shown by co-immunoprecipitation (Co-IP), and suppressed Cx43 ubiquitination and degradation, competitively inhibiting the binding of Cx43 with Nedd4. Thus Nedd4 could not bind and ubiquitinate Cx43, leading to the up-regulation of Cx43 and phosphorylation of Cx43 at S282.

CONCLUSIONS

FGF21 inhibited the effects of Dox on cardiomyocytes by elevating the phosphorylation of Cx43 at S282 and total Cx43 expression. This study suggests a previously unknown mechanism for the FGF21-mediated enhancement of cardiomyocyte survival and provides an effective approach to protect against the adverse cardiac effects of Dox.

Emerging Evidence Linking the Liver to the Cardiovascular System: Liver-derived Secretory Factors

Cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality worldwide. Recently, accumulating evidence has revealed hepatic mediators, termed as liver-derived secretory factors (LDSFs), play an important role in regulating CVDs such as atherosclerosis, coronary artery disease, thrombosis, myocardial infarction, heart failure, metabolic cardiomyopathy, arterial hypertension, and pulmonary hypertension. LDSFs presented here consisted of microbial metabolite, extracellular vesicles, proteins, and microRNA, they are primarily or exclusively synthesized and released by the liver, and have been shown to exert pleiotropic actions on cardiovascular system. LDSFs mainly target vascular endothelial cell, vascular smooth muscle cells, cardiomyocytes, fibroblasts, macrophages and platelets, and further modulate endothelial nitric oxide synthase/nitric oxide, endothelial function, energy metabolism, inflammation, oxidative stress, and dystrophic calcification. Although some LDSFs are known to be detrimental/beneficial, controversial findings were also reported for many. Therefore, more studies are required to further explore the causal relationships between LDSFs and CVDs and uncover the exact mechanisms, which is expected to extend our understanding of the crosstalk between the liver and cardiovascular system and identify potential therapeutic targets. Furthermore, in the case of patients with liver disease, awareness should be given to the implications of these abnormalities in the cardiovascular system. These studies also underline the importance of early recognition and intervention of liver abnormalities in the practice of cardiovascular care, and a multidisciplinary approach combining hepatologists and cardiologists would be more preferable for such patients.

Mechanisms Linking Metabolic-Associated Fatty Liver Disease (MAFLD) to Cardiovascular Disease

PURPOSE OF REVIEW

Metabolic-associated fatty liver disease (MAFLD) is a condition of fat accumulation in the liver that occurs in the majority of patients in combination with metabolic dysfunction in the form of overweight or obesity. In this review, we highlight the cardiovascular complications in MAFLD patients as well as some potential mechanisms linking MAFLD to the development of cardiovascular disease and highlight potential therapeutic approaches to treating cardiovascular diseases in patients with MAFLD.

RECENT FINDINGS

MAFLD is associated with an increased risk of cardiovascular diseases (CVD), including hypertension, atherosclerosis, cardiomyopathies, and chronic kidney disease. While clinical data have demonstrated the link between MAFLD and the increased risk of CVD development, the mechanisms responsible for this increased risk remain unknown. MAFLD can contribute to CVD through several mechanisms including its association with obesity and diabetes, increased levels of inflammation, and oxidative stress, as well as alterations in hepatic metabolites and hepatokines. Therapies to potentially treat MAFLD-induced include statins and lipid-lowering drugs, glucose-lowering agents, antihypertensive drugs, and antioxidant therapy.

Fibroblast growth factor 21 in metabolic syndrome

Metabolic syndrome is a complex metabolic disorder that often clinically manifests as obesity, insulin resistance/diabetes, hyperlipidemia, and hypertension. With the development of social and economic systems, the incidence of metabolic syndrome is increasing, bringing a heavy medical burden. However, there is still a lack of effective prevention and treatment strategies. Fibroblast growth factor 21 (FGF21) is a member of the human FGF superfamily and is a key protein involved in the maintenance of metabolic homeostasis, including reducing fat mass and lowering hyperglycemia, insulin resistance and dyslipidemia. Here, we review the current regulatory mechanisms of FGF21, summarize its role in obesity, diabetes, hyperlipidemia, and hypertension, and discuss the possibility of FGF21 as a potential target for the treatment of metabolic syndrome.

The associations of adipokines with hypertension in youth with cardiometabolic risk and the mediation role of insulin resistance: The BCAMS study

The mechanisms link obesity and hypertension are not well understood. One possibility is the alterations in adipose-derived adipokines that modulate insulin resistance (IR) and cardiovascular homeostasis. We aimed to assess the associations between hypertension and four adipokine levels in Chinese youth, and to examine to what extent the associations are mediated by IR. We utilized cross-sectional data from the Beijing Children and Adolescents Metabolic Syndrome (BCAMS) Study Cohort (n = 559, mean age = 20.2 years). Plasma leptin, adiponectin, retinol binding protein 4 (RBP4) and fibroblast growth factor 21 (FGF21) levels were assayed. The relationships between adipokines and hypertension and the possible mediation effect of IR were evaluated. Youth with hypertension have lower adiponectin and higher leptin, FGF21 (all P < 0.001) and RBP4 levels (p = 0.06) compared to their counterparts. Moreover, the co-existence of these two or more adipokine abnormalities in youth leads to a 9-fold increased risk for hypertension (OR: 9.19; 95% CI, 4.01-21.08) compared with these without abnormalities. However, in the fully adjusted and BMI-adjusted analyses, only FGF21 was a significant predictor of hypertension (OR: 2.12; 95% CI, 1.34-3.36). Mediation analysis revealed that the associations between leptin, adiponectin, RBP4 and hypertension are totally mediated by IR (proportion: 63.9%, 65.4%, and 31.6%, respectively), while BMI and IR partly mediated the association between FGF21 and hypertension (proportion: 30.6%, 21.2%). Our findings suggest that dysregulation of adipokines might result in hypertension in youth. Leptin, adiponectin and RBP4 may exert their functions in hypertension through adiposity-related IR, whereas FGF21 might be used as an independent marker of hypertension in youth.

Mas receptor: a potential strategy in the management of ischemic cardiovascular diseases

MasR is a critical element in the RAS accessory pathway that protects the heart against myocardial infarction, ischemia-reperfusion injury, and pathological remodeling by counteracting the effects of AT1R. This receptor is mainly stimulated by Ang 1-7, which is a bioactive metabolite of the angiotensin produced by ACE2. MasR activation attenuates ischemia-related myocardial damage by facilitating vasorelaxation, improving cell metabolism, reducing inflammation and oxidative stress, inhibiting thrombosis, and stabilizing atherosclerotic plaque. It also prevents pathological cardiac remodeling by suppressing hypertrophy- and fibrosis-inducing signals. In addition, the potential of MasR in lowering blood pressure, improving blood glucose and lipid profiles, and weight loss has made it effective in modulating risk factors for coronary artery disease including hypertension, diabetes, dyslipidemia, and obesity. Considering these properties, the administration of MasR agonists offers a promising approach to the prevention and treatment of ischemic heart disease.Abbreviations: Acetylcholine (Ach); AMP-activated protein kinase (AMPK); Angiotensin (Ang); Angiotensin receptor (ATR); Angiotensin receptor blocker (ARB); Angiotensin-converting enzyme (ACE); Angiotensin-converting enzyme inhibitor (ACEI); Anti-PRD1-BF1-RIZ1 homologous domain containing 16 (PRDM16); bradykinin (BK); Calcineurin (CaN); cAMP-response element binding protein (CREB); Catalase (CAT); C-C Motif Chemokine Ligand 2 (CCL2); Chloride channel 3 (CIC3); c-Jun N-terminal kinases (JNK); Cluster of differentiation 36 (CD36); Cocaine- and amphetamine-regulated transcript (CART); Connective tissue growth factor (CTGF); Coronary artery disease (CAD); Creatine phosphokinase (CPK); C-X-C motif chemokine ligand 10 (CXCL10); Cystic fibrosis transmembrane conductance regulator (CFTR); Endothelial nitric oxide synthase (eNOS); Extracellular signal-regulated kinase 1/2 (ERK 1/2); Fatty acid transport protein (FATP); Fibroblast growth factor 21 (FGF21); Forkhead box protein O1 (FoxO1); Glucokinase (Gk); Glucose transporter (GLUT); Glycogen synthase kinase 3β (GSK3β); High density lipoprotein (HDL); High sensitive C-reactive protein (hs-CRP); Inositol trisphosphate (IP3); Interleukin (IL); Ischemic heart disease (IHD); Janus kinase (JAK); Kruppel-like factor 4 (KLF4); Lactate dehydrogenase (LDH); Left ventricular end-diastolic pressure (LVEDP); Left ventricular end-systolic pressure (LVESP); Lipoprotein lipase (LPL); L-NG-Nitro arginine methyl ester (L-NAME); Low density lipoprotein (LDL); Mammalian target of rapamycin (mTOR); Mas-related G protein-coupled receptors (Mrgpr); Matrix metalloproteinase (MMP); MAPK phosphatase-1 (MKP-1); Mitogen-activated protein kinase (MAPK); Monocyte chemoattractant protein-1 (MCP-1); NADPH oxidase (NOX); Neuropeptide FF (NPFF); Neutral endopeptidase (NEP); Nitric oxide (NO); Nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB); Nuclear-factor of activated T-cells (NFAT); Pancreatic and duodenal homeobox 1 (Pdx1); Peroxisome proliferator- activated receptor γ (PPARγ); Phosphoinositide 3-kinases (PI3k); Phospholipase C (PLC); Prepro-orexin (PPO); Prolyl-endopeptidase (PEP); Prostacyclin (PGI2); Protein kinase B (Akt); Reactive oxygen species (ROS); Renin-angiotensin system (RAS); Rho-associated protein kinase (ROCK); Serum amyloid A (SAA); Signal transducer and activator of transcription (STAT); Sirtuin 1 (Sirt1); Slit guidance ligand 3 (Slit3); Smooth muscle 22α (SM22α); Sterol regulatory element-binding protein 1 (SREBP-1c); Stromal-derived factor-1a (SDF); Superoxide dismutase (SOD); Thiobarbituric acid reactive substances (TBARS); Tissue factor (TF); Toll-like receptor 4 (TLR4); Transforming growth factor β1 (TGF-β1); Tumor necrosis factor α (TNF-α); Uncoupling protein 1 (UCP1); Ventrolateral medulla (VLM).

Fibroblast growth factor 21 resistance is associated with body shape in patients with type 2 diabetes complicating hypertension

Objectives

Obesity, especially abdominal obesity, increases the prevalence of metabolic and cardiovascular disease (CVD). Fibroblast growth factor 21 (FGF21) has been identified as a critical regulator playing a therapeutic role in diabetes and its complications. This study aims to evaluate the relationship between serum FGF21 levels and body shape parameters in patients with hypertension (HP) and type 2 diabetes mellitus (T2DM).

Methods

Serum FGF21 levels were determined in 1,003 subjects, including 745 patients with T2DM, and 258 individuals were selected as a healthy control in this cross-sectional study.

Results

Serum FGF21 levels were significantly higher in T2DM patients with HP than those without [534.9 (322.6-722.2) vs. 220.65 (142.8-347.55) pg/ml, p < 0.001], and levels in both of these two groups were significantly increased compared with that of healthy control [123.92 (67.23-219.32) pg/ml, all p < 0.001]. These differences were also observed in body shape parameters, including weight, waistline, body mass index (BMI), body shape index (ABSI), and the percentage of abdominal obesity. Serum FGF21 levels in T2DM patients were positively correlated with body shape parameters, including weight, waistline, neck circumference, BMI, ABSI, percent of abdominal obesity, and triglyceride, while negatively with estimated glomerular filtration rate (all p < 0.01). The significance remained stable when adjusted for age and T2DM duration. In addition, both serum FGF21 concentrations and waistline were independently associated with HP in T2DM patients after the adjustment for risk factors (all p < 0.05). ROC analysis for FGF21 levels of 745 patients with T2DM identified 411.33 pg/ml as an optimal cut-off point to predict HP, with a sensitivity and specificity of 66.0% and 84.9%, respectively.

Conclusions

FGF21 resistance occurs in patients of HP in T2DM, and positively correlates with body shape parameters (especially waistline and BMI). High levels of FGF21 may be a compensatory reaction to offset HP.

Mechanism of fibroblast growth factor 21 in cardiac remodeling

Cardiac remodeling is a basic pathological process that enables the progression of multiple cardiac diseases to heart failure. Fibroblast growth factor 21 is considered a regulator in maintaining energy homeostasis and shows a positive role in preventing damage caused by cardiac diseases. This review mainly summarizes the effects and related mechanisms of fibroblast growth factor 21 on pathological processes associated with cardiac remodeling, based on a variety of cells of myocardial tissue. The possibility of Fibroblast growth factor 21 as a promising treatment for the cardiac remodeling process will also be discussed.

Fibroblast growth factor-21 is required for weight loss induced by the glucagon-like peptide-1 receptor agonist liraglutide in male mice fed high carbohydrate diets

OBJECTIVE

Glucagon-like peptide-1 receptor (GLP-1R) agonists (GLP-1RA) and fibroblast growth factor-21 (FGF21) confer similar metabolic benefits. GLP-1RA induce FGF21, leading us to investigate mechanisms engaged by the GLP-1RA liraglutide to increase FGF21 levels and the metabolic relevance of liraglutide-induced FGF21.

METHODS

Circulating FGF21 levels were measured in fasted male C57BL/6J, neuronal GLP-1R knockout, β-cell GLP-1R knockout, and liver peroxisome proliferator-activated receptor alpha knockout mice treated acutely with liraglutide. To test the metabolic relevance of liver FGF21 in response to liraglutide, chow-fed control and liver Fgf21 knockout (LivFgf21-/-) mice were treated with vehicle or liraglutide in metabolic chambers. Body weight and composition, food intake, and energy expenditure were measured. Since FGF21 reduces carbohydrate intake, we measured body weight in mice fed matched diets with low- (LC) or high-carbohydrate (HC) content and in mice fed a high-fat, high-sugar (HFHS) diet. This was done in control and LivFgf21-/- mice and in mice lacking neuronal β-klotho (Klb) expression to disrupt brain FGF21 signaling.

RESULTS

Liraglutide increases FGF21 levels independently of decreased food intake via neuronal GLP-1R activation. Lack of liver Fgf21 expression confers resistance to liraglutide-induced weight loss due to attenuated reduction of food intake in chow-fed mice. Liraglutide-induced weight loss was impaired in LivFgf21-/- mice when fed HC and HFHS diets but not when fed a LC diet. Loss of neuronal Klb also attenuated liraglutide-induced weight loss in mice fed HC or HFHS diets.

CONCLUSIONS

Our findings support a novel role for a GLP-1R-FGF21 axis in regulating body weight in a dietary carbohydrate-dependent manner.

Increased serum fibroblast growth factor 21 levels are associated with adverse clinical outcomes after intracerebral hemorrhage

Introduction

Intracerebral hemorrhage (ICH) is the most prevalent cause of death. We sought to explore whether serum Fibroblast growth factor 21 (FGF21) is of substantial benefit in predicting poor prognosis in ICH patient.

Methods

A prospective, multicenter cohort analysis of serum FGF21 levels in 418 ICH patients was carried out. At three months following ICH start, the primary endpoint was death or major disability, whereas the secondary endpoint was death. We investigated the association between serum FGF21 and clinical outcomes. We added FGF21 to the existing rating scale to assess whether it enhanced the prediction ability of the original model. Effectiveness was determined by calculating the C-statistic, net reclassification index (NRI), absolute integrated discrimination improvement (IDI) index.

Results

Among 418 enrolled patients, 217 (51.9%) of the all subjects had death or significant disability. Compared with patients in the lowest quartile group, those in the first quartile group had higher risk of the primary outcome (Odds ratio, 2.73 [95%CI,1.42-5.26, p < 0.05]) and second outcome (Hazard ratio, 4.28 [95%CI,1.61-11.42, p < 0.001]). The integration of FGF21 into many current ICH scales improved the discrimination and calibration quality for the integrated discrimination index's prediction of main and secondary findings (all p < 0.05).

Conclusion

Elevated serum FGF21 is associated with increased risks of adverse clinical outcomes at 3 months in ICH patients, suggesting FGF21 may be a valuable prognostic factor.

Hyperactivation of YAP/TAZ Drives Alterations in Mesangial Cells through Stabilization of N-Myc in Diabetic Nephropathy

SIGNIFICANCE STATEMENT

Mesangial cells (MCs) in the kidney are essential to maintaining glomerular integrity, and their impairment leads to major glomerular diseases including diabetic nephropathy (DN). Although high blood glucose elicits abnormal alterations in MCs, the underlying mechanism is poorly understood. We show that YAP/TAZ are increased in MCs of patients with DN and two animal models of DN. High glucose directly induces activation of YAP/TAZ through the canonical Hippo pathway in cultured MCs. Hyperactivation of YAP/TAZ in mouse MCs recapitulates the hallmarks of DN. Activated YAP/TAZ bind and stabilize N-Myc, one of the Myc family. N-Myc stabilization leads to aberrant enhancement of its transcriptional activity and to MC impairments. Our findings shed light on how high blood glucose in diabetes mellitus leads to DN and support a rationale that lowering blood glucose in diabetes mellitus could delay DN pathogenesis.

BACKGROUND

Mesangial cells (MCs) in the kidney are central to maintaining glomerular integrity, and their impairment leads to major glomerular diseases, including diabetic nephropathy (DN). Although high blood glucose elicits abnormal alterations in MCs, the underlying molecular mechanism is poorly understood.

METHODS

Immunolocalization of YAP/TAZ and pathological features of PDGFRβ + MCs were analyzed in the glomeruli of patients with DN, in Zucker diabetic fatty rats, and in Lats1/2i ΔPβ mice. RiboTag bulk-RNA sequencing and transcriptomic analysis of gene expression profiles of the isolated MCs from control and Lats1/2iΔPβ mice were performed. Immunoprecipitation analysis and protein stability of N-Myc were performed by the standard protocols.

RESULTS

YAP and TAZ, the final effectors of the Hippo pathway, are highly increased in MCs of patients with DN and in Zucker diabetic fatty rats. Moreover, high glucose directly induces activation of YAP/TAZ through the canonical Hippo pathway in cultured MCs. Hyperactivation of YAP/TAZ in mouse model MCs recapitulates the hallmarks of DN, including excessive proliferation of MCs and extracellular matrix deposition, endothelial cell impairment, glomerular sclerosis, albuminuria, and reduced glomerular filtration rate. Mechanistically, activated YAP/TAZ bind and stabilize N-Myc protein, one of the Myc family of oncogenes. N-Myc stabilization leads to aberrant enhancement of its transcriptional activity and eventually to MC impairments and DN pathogenesis.

CONCLUSIONS

Our findings shed light on how high blood glucose in diabetes mellitus leads to DN and support a rationale that lowering blood glucose in diabetes mellitus could delay DN pathogenesis.

Cardiac Hepatopathy: New Perspectives on Old Problems through a Prism of Endogenous Metabolic Regulations by Hepatokines

Cardiac hepatopathy refers to acute or chronic liver damage caused by cardiac dysfunction in the absence of any other possible causative reasons of liver injury. There is a large number of evidence of the fact that cardiac hepatopathy is associated with poor clinical outcomes in patients with acute or actually decompensated heart failure (HF). However, the currently dominated pathophysiological background does not explain a role of metabolic regulative proteins secreted by hepatocytes in progression of HF, including adverse cardiac remodeling, kidney injury, skeletal muscle dysfunction, osteopenia, sarcopenia and cardiac cachexia. The aim of this narrative review was to accumulate knowledge of hepatokines (adropin; fetuin-A, selenoprotein P, fibroblast growth factor-21, and alpha-1-microglobulin) as adaptive regulators of metabolic homeostasis in patients with HF. It is suggested that hepatokines play a crucial, causative role in inter-organ interactions and mediate tissue protective effects counteracting oxidative stress, inflammation, mitochondrial dysfunction, apoptosis and necrosis. The discriminative potencies of hepatokines for HF and damage of target organs in patients with known HF is under on-going scientific discussion and requires more investigations in the future.

Flavonifractor plautii Protects Against Elevated Arterial Stiffness

BACKGROUND

Dysbiosis of gut microbiota plays a pivotal role in vascular dysfunction and microbial diversity was reported to be inversely correlated with arterial stiffness. However, the causal role of gut microbiota in the progression of arterial stiffness and the specific species along with the molecular mechanisms underlying this change remain largely unknown.

METHODS

Participants with elevated arterial stiffness and normal controls free of medication were matched for age and sex. The microbial composition and metabolic capacities between the 2 groups were compared with the integration of metagenomics and metabolomics. Subsequently, Ang II (angiotensin II)-induced and humanized mouse model were employed to evaluate the protective effect of Flavonifractor plautii (F plautii) and its main effector cis-aconitic acid.

RESULTS

Human fecal metagenomic sequencing revealed a significantly high abundance and centrality of F plautii in normal controls, which was absent in the microbial community of subjects with elevated arterial stiffness. Moreover, blood pressure only mediated part of the effect of F plautii on lower arterial stiffness. The microbiome of normal controls exhibited an enhanced capacity for glycolysis and polysaccharide degradation, whereas, those of subjects with increased arterial stiffness were characterized by increased biosynthesis of fatty acids and aromatic amino acids. Integrative analysis with metabolomics profiling further suggested that increased cis-aconitic acid served as the main effector for the protective effect of F plautii against arterial stiffness. Replenishment with F plautii and cis-aconitic acid improved elastic fiber network and reversed increased pulse wave velocity through the suppression of MMP-2 (matrix metalloproteinase-2) and inhibition of MCP-1 (monocyte chemoattractant protein-1) and NF-κB (nuclear factor kappa-B) activation in both Ang II-induced and humanized model of arterial stiffness.

CONCLUSIONS

Our translational study identifies a novel link between F plautii and arterial function and raises the possibility of sustaining vascular health by targeting gut microbiota.