The Metabolic Role of GRK2 in Insulin Resistance and Associated Conditions

Network pharmacology analysis revealed the mechanism and active compounds of jiao tai wan in the treatment of type 2 diabetes mellitus via SRC/PI3K/AKT signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Jiao-tai-wan (JTW) is a traditional Chinese herbal prescription, exerts its therapeutic effects on type 2 diabetes mellitus (T2DM). However, its mechanisms and active components remain unclear.

AIM OF THE STUDY

To investigate the therapeutic mechanisms of JTW in treating type 2 diabetes mellitus (T2DM), focusing on identifying active components, their targets, and validating efficacy through SRC/PI3K/AKT signaling pathway modulation in vitro and in vivo.

MATERIALS AND METHODS

Active ingredients were retrieved from the Traditional Chinese Medicine System Pharmacology (TCMSP) and Comprehensive Traditional Chinese Medicine Database (TCMID). Targets for these components were identified using the ChemMapper database based on 3D structural similarity. T2DM-related genes were sourced from the DisGeNET and Gene Expression Omnibus (GEO) databases. Protein-protein interaction (PPI) analysis and functional enrichment analysis were conducted to construct a pathway network of "herbs-active ingredients-candidate targets", identifying core molecular mechanisms and key active ingredients. SwissDock was used for molecular docking to predict ligands for candidate targets. The diabetic models were established using C57BL/6 mice and human liver HepG2 cell lines. Their Effectiveness and key molecules were verified through biochemical detection and immunoblotting.

RESULTS

Total 30 active compounds, 597 active ingredient targets, 9631 T2DM-related genes, and 521 overlapping candidate targets were found for JTW on T2DM. Go enrichment indicated the core pathways enriched on insulin and glucose metabolism. The auto-docking demonstrated SRC has potential binds to ingredients of JTW. In vivo, JTW can reduce blood glucose, and blood lipid levels, and HOMA-IR, and increase HOMA-ISI levels in T2DM mice with reduced ALT, AST, MDA levels and increased SOD levels. Meanwhile, decreased phosphorylation of SRC, along with increased levels of phosphorylated PI3K, PI3K, and phosphorylated AKT, were observed. HE staining of liver tissues further confirmed that JTW administration improved liver morphology, reducing inflammation and necrosis. In vitro, JTW significantly ameliorates upstream dysregulation by reducing SRC phosphorylation while enhancing phosphorylated PI3K, PI3K, and AKT phosphorylation levels.

CONCLUSION

JTW may alleviate glucose, insulin resistance, and lipid metabolism disorders by the SRC/PI3K/AKT signaling pathway, that provide a novel view of potential active compounds and essential targets in treating T2DM.

Cinnamaldehyde activates AMPK/PGC-1α pathway via targeting GRK2 to ameliorate heart failure

BACKGROUND

According to recent research, treating heart failure (HF) by inhibiting G protein-coupled receptor kinase 2 (GRK2) to improve myocardial energy metabolism has been identified as a potential approach. Cinnamaldehyde (CIN), a phenylpropyl aldehyde compound, has been demonstrated to exhibit beneficial effects in cardiovascular diseases. However, whether CIN inhibits GRK2 to ameliorate myocardial energy metabolism in HF is still unclear.

PURPOSE

This study examines the effects of CIN on GRK2 and myocardial energy metabolism to elucidate its underlying mechanism to treat HF.

METHODS

The isoproterenol (ISO) induced HF model in vivo and in vitro were constructed using Sprague-Dawley (SD) rats and primary neonatal rat cardiomyocytes (NRCMs). Based on this, the effects of CIN on myocardial energy metabolism and GRK2 were investigated. Additionally, validation experiments were conducted after interfering and over-expressing GRK2 in ISO-induced NRCMs to verify the regulatory effect of CIN on GRK2. Furthermore, binding capacity between GRK2 and CIN was explored by Cellular Thermal Shift Assay (CETSA) and Microscale Thermophoresis (MST).

RESULTS

In vivo and in vitro, CIN significantly improved HF as demonstrated by reversing abnormal changes in myocardial injury markers, inhibiting myocardial hypertrophy and decreasing myocardial fibrosis. Additionally, CIN promoted myocardial fatty acid metabolism to ameliorate myocardial energy metabolism disorder by activating AMPK/PGC-1α signaling pathway. Moreover, CIN reversed the inhibition of myocardial fatty acid metabolism and AMPK/PGC-1α signaling pathway by GRK2 over-expression in ISO-induced NRCMs. Meanwhile, CIN had no better impact on the stimulation of cardiac fatty acid metabolism and the AMPK/PGC-1α signaling pathway in ISO-induced NRCMs when GRK2 was disrupted. Noticeably, CETSA and MST confirmed that CIN binds to GRK2 directly. The binding of CIN and GRK2 promoted the ubiquitination degradation of GRK2 mediated by murine double mimute 2.

CONCLUSION

This study demonstrates that CIN exerts a protective intervention in HF by targeting GRK2 and promoting its ubiquitination degradation to activate AMPK/PGC-1α signaling pathway, ultimately improving myocardial fatty acid metabolism.

Prediabetes Increases the Risk of Frailty in Prefrail Older Adults With Hypertension: Beneficial Effects of Metformin

BACKGROUND

Prediabetes has garnered increasing attention due to its association with cardiovascular conditions, especially hypertension, which heightens the risk of prefrailty and frailty among older individuals.

METHODS

We screened elders with prefrail hypertension from March 2021 to January 2023. We assessed the correlation linking cognitive dysfunction (Montreal Cognitive Assessment score), insulin resistance (triglyceride-to-glucose index), and physical impairment (5-meter gait speed). Then, we measured the risk of developing frailty after a 1-year follow-up period, adjusting the outcome using multivariable Cox regression analysis. We also investigated the impact of administering 500 mg of metformin once daily to a subset of frail subjects for an additional 6 months.

RESULTS

We assessed the relationship between the triglyceride-to-glucose index and the Montreal Cognitive Assessment score, observing a significant correlation (r, 0.880; P<0.0001). Similarly, we analyzed the association between the triglyceride-to-glucose index and 5-meter gait speed, uncovering a significant link between insulin resistance and physical impairment (r, 0.809; P<0.0001). Prediabetes was found to significantly (P<0.0001) elevate the risk of frailty development compared with individuals without prediabetes by the end of the 1-year follow-up, a finding confirmed via multivariable analysis with Cox regression. Furthermore, among the subgroup of subjects who developed frailty, those who received metformin exhibited a significant decrease in frailty levels (P<0.0001).

CONCLUSIONS

Insulin resistance and prediabetes play substantial roles in the development of cognitive and physical impairments, highlighting their importance in managing hypertension, even before the onset of frank diabetes. Metformin, a well-established drug for the treatment of diabetes, has shown favorable effects in mitigating frailty.

Hepatic GRK2 is dispensable for glucose homeostasis and other key metabolic parameters in mice

OBJECTIVE

G-protein-coupled receptor (GPCR) kinases (GRKs) abrogate GPCR signaling by promoting receptor desensitization and internalization. Accumulating evidence suggests that GRK2 represents an important regulator of GPCR-mediated effects on systemic glucose metabolism, obesity, and insulin resistance. Despite the key role of the liver in maintaining euglycemia, the potential metabolic relevance of hepatic GRK2 has yet to be examined. Thus, the goal of this study was to explore the potential role of hepatic GRK2 in maintaining glucose homeostasis and other key metabolic functions.

METHODS

To address this question, we generated mice that showed a ∼90% reduction in GRK2 protein expression selectively in hepatocytes (Hep-GRK2-KO mice) and subjected these mice, together with their control littermates, to systematic metabolic phenotyping studies.

RESULTS

We found that Hep-GRK2-KO mice maintained on regular chow did not differ significantly from their control littermates in glycemia, glucose tolerance, insulin sensitivity, in vivo gluconeogenesis, and glucagon-induced hyperglycemia. We obtained similar findings when we analyzed Hep-GRK2-KO mice and control littermates consuming an obesogenic high-fat diet. Likewise, plasma levels of insulin, glucagon, free fatty acids, and ketone bodies remained unaffected by the lack of hepatocyte GRK2. The same was true when we examined the expression levels of key genes regulating hepatic glucose and fatty acid metabolism.

CONCLUSION

In summary, our data suggest that hepatocyte GRK2 is dispensable for systemic glucose homeostasis and other key metabolic functions in both lean and obese mice. This finding suggests that drug development efforts aimed at inhibiting GRK2 to improve impaired glucose homeostasis and insulin sensitivity need to focus on other metabolically important tissues.

Acute heart failure: mechanisms and pre-clinical models-a Scientific Statement of the ESC Working Group on Myocardial Function

While chronic heart failure (CHF) treatment has considerably improved patient prognosis and survival, the therapeutic management of acute heart failure (AHF) has remained virtually unchanged in the last decades. This is partly due to the scarcity of pre-clinical models for the pathophysiological assessment and, consequently, the limited knowledge of molecular mechanisms involved in the different AHF phenotypes. This scientific statement outlines the different trajectories from acute to CHF originating from the interaction between aetiology, genetic and environmental factors, and comorbidities. Furthermore, we discuss the potential molecular targets capable of unveiling new therapeutic perspectives to improve the outcome of the acute phase and counteracting the evolution towards CHF.

Interventions to Address Cardiovascular Risk in Obese Patients: Many Hands Make Light Work

Obesity is a growing public health epidemic worldwide and is implicated in slowing improved life expectancy and increasing cardiovascular (CV) risk; indeed, several obesity-related mechanisms drive structural, functional, humoral, and hemodynamic heart alterations. On the other hand, obesity may indirectly cause CV disease, mediated through different obesity-associated comorbidities. Diet and physical activity are key points in preventing CV disease and reducing CV risk; however, these strategies alone are not always sufficient, so other approaches, such as pharmacological treatments and bariatric surgery, must support them. Moreover, these strategies are associated with improved CV risk factors and effectively reduce the incidence of death and CV events such as myocardial infarction and stroke; consequently, an individualized care plan with a multidisciplinary approach is recommended. More precisely, this review explores several interventions (diet, physical activity, pharmacological and surgical treatments) to address CV risk in obese patients and emphasizes the importance of adherence to treatments.

GRK2-Targeted Knockdown as Therapy for Multiple System Atrophy

BACKGROUND

Multiple system atrophy (MSA) is a sporadic adult-onset rare neurodegenerative synucleinopathy for which counteracting central nervous system insulin resistance bears the potential of being neuroprotective. G-protein-(heterotrimeric guanine nucleotide-binding protein)-coupled receptor kinase 2 (GRK2) is emerging as a physiologically relevant inhibitor of insulin signaling.

OBJECTIVES

We tested whether lowering brain GRK2 abundance may reverse insulin-resistance.

METHODS

We lowered brain GRK2 abundance through viral-mediated delivery of a GRK2-specific miRNA and quantified the reversion of a developing or an established insulin-resistant phenotype using the transgenic PLP-SYN mouse model of MSA.

RESULTS

Viral vector delivery of a GRK2 miRNA demonstrated a neuroprotective capacity when administered (1) in utero intracerebroventricularly in developing PLP-SYN mice and (2) intrastriatally in adult PLP-SYN mice. Decreased striatal GRK2 levels correlated in both designs with neuroprotection of the substantia nigra dopamine neurons, reduction in high-molecular-weight species of α-synuclein, and reduced insulin resistance.

CONCLUSIONS

These data support GRK2 as a potential therapeutic target in MSA. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Artificial Intelligence in Hypertension Management: An Ace up Your Sleeve

Arterial hypertension (AH) is a progressive issue that grows in importance with the increased average age of the world population. The potential role of artificial intelligence (AI) in its prevention and treatment is firmly recognized. Indeed, AI application allows personalized medicine and tailored treatment for each patient. Specifically, this article reviews the benefits of AI in AH management, pointing out diagnostic and therapeutic improvements without ignoring the limitations of this innovative scientific approach. Consequently, we conducted a detailed search on AI applications in AH: the articles (quantitative and qualitative) reviewed in this paper were obtained by searching journal databases such as PubMed and subject-specific professional websites, including Google Scholar. The search terms included artificial intelligence, artificial neural network, deep learning, machine learning, big data, arterial hypertension, blood pressure, blood pressure measurement, cardiovascular disease, and personalized medicine. Specifically, AI-based systems could help continuously monitor BP using wearable technologies; in particular, BP can be estimated from a photoplethysmograph (PPG) signal obtained from a smartphone or a smartwatch using DL. Furthermore, thanks to ML algorithms, it is possible to identify new hypertension genes for the early diagnosis of AH and the prevention of complications. Moreover, integrating AI with omics-based technologies will lead to the definition of the trajectory of the hypertensive patient and the use of the most appropriate drug. However, AI is not free from technical issues and biases, such as over/underfitting, the "black-box" nature of many ML algorithms, and patient data privacy. In conclusion, AI-based systems will change clinical practice for AH by identifying patient trajectories for new, personalized care plans and predicting patients' risks and necessary therapy adjustments due to changes in disease progression and/or therapy response.

G Protein-Coupled Receptor Kinases Take Central Stage

The relevance of the family of G protein-coupled receptor kinases (GRKs) is based on its key participation in the regulation and intracellular dynamics of the largest family of membrane receptors, namely G protein-coupled receptors (GPCRs) [...].

Orlistat Resensitizes Sorafenib-Resistance in Hepatocellular Carcinoma Cells through Modulating Metabolism

Sorafenib is one of the options for advanced hepatocellular carcinoma treatment and has been shown to extend median overall survival. However, sorafenib resistance often develops a few months after treatment. Hence, developing various strategies to overcome sorafenib resistance and understand the possible mechanisms is urgently needed. We first established sorafenib-resistant hepatocellular carcinoma (HCC) cells. Then, we found that sorafenib-resistant Huh7 cells (Huh7/SR) exhibit higher glucose uptakes and express elevated fatty acid synthesis and glucose metabolism-related proteins than their parental counterparts (Huh7). The current study investigated whether sorafenib resistance could be reversed by suppressing fatty acid synthesis, using a fatty acid synthase (FASN) inhibitor, orlistat, in HCC cells. FASN inhibition-caused changes in protein expressions and cell cycle distribution were analyzed by Western blot and flow cytometry, and changes in glucose uptakes were also evaluated by ¹⁸F-FDG uptake. Orlistat remarkably enhanced the cytotoxicity of sorafenib in both Huh7 and Huh7/SR cells, and flow cytometry showed that combination treatment significantly increased the sub-G1 population in both cell lines. Western blot revealed that the combination treatment effectively increased the ratio of Bax/Bcl-2 and decreased expressions of pERK; additionally, the combination treatment also strongly suppressed fatty acid synthesis-related proteins (e.g., FASN and SCD) in both cell lines. Lastly, the ¹⁸F-FDG uptake was repressed by the combination treatment in both cell lines. Our results indicated that orlistat-mediated FASN inhibition could overcome sorafenib resistance and enhance cell killing in HCC by changing cell metabolism.

A Multistep Approach to Deal With Advanced Heart Failure: A Case Report on the Positive Effect of Cardiac Contractility Modulation Therapy on Pulmonary Pressure Measured by CardioMEMS

During the last years, the management of heart failure (HF) made substantial progress, focusing on device-based therapies to meet the demands of this complex syndrome. In this case report, we present a multistep approach to deal with HF. Specifically, we report the first patient subjected to the implantation of both Optimizer Smart^® (Impulse Dynamics Inc., Marlton, NJ, USA) and CardioMEMS devices. A 72-year-old male patient with HF and reduced ejection fraction (HFrEF) was admitted to our cardiology department in January 2021, following a progressive shortening of the time between hospitalizations for levosimendan infusions. Specifically, the patient was monitored daily by CardioMEMS, and a strategy of levosimendan infusions guided by the device had been adopted. He was also a carrier of MitraClips and cardiac resynchronization therapy defibrillator (CRT-D) and had optimized HF medical therapy. In January 2021, the patient implanted Optimizer Smart^® device for cardiac contractility modulation (CCM) therapy because of poor response to therapy and elevated pulmonary artery pressure (PAP). CCM significantly reduced PAP values following discharge (systolic PAP 33.67 ± 2.92 vs. 40.6 ± 3.37 mmHg, diastolic PAP 14.5 ± 2.01 vs. 22.5 ± 2.53 mmHg, mean PAP 22.87 ± 2.20 vs. 30.9 ± 2.99 mmHg, HR 60.93 ± 1.53 vs. 80.83 ± 3.66 bpm; p < 0.0001), with persisting effect at 9 months. The usefulness of CCM is objectively demonstrated for the first time by continuous invasive monitoring of PAP by CardioMEMS, which can suggest the correct timing for CCM implantation.

Triglyceride-Glucose Index for the Diagnosis of Metabolic Syndrome: A Cross-Sectional Study of 298,652 Individuals Receiving a Health Check-Up in China

OBJECTIVE

We herein aim to explore the relationship between the triglyceride-glucose (TyG) index and metabolic syndrome (MS).

METHODS

We enrolled 298,652 individuals with an average age of 47.08 ± 12.94 years and who underwent health check-ups at the First Affiliated Hospital of Wuhu Wannan Medical College in this cross-sectional study from 2014 to 2016. We enlisted 125,025 women (41.86%) and 173,627 men (58.14%). The survey information included a questionnaire survey, a physical examination, and a laboratory examination.

RESULTS

The prevalence of MS increased gradually in the TyG-index subgroups (Q1, TyG <8.30; Q2, 8.30≤ TyG <8.83; and Q3, TyG ≥8.83). We noted significant differences in hypertension, hyperlipidemia, hyperglycemia, sex, age, body mass index (BMI), smoking and drinking habits, and estimated glomerular filtration rate between the TyG-index subgroups. Multiclass logistic regression analysis showed that the group with TyG <8.30 was the reference group, and the 8.30≤ TyG <8.83 and the TyG ≥8.83 groups exhibited a higher TyG index with MS, and a lower TyG index without MS disease. In the linear curve analysis of the TyG index and MS components, BMI, systolic blood pressure, and diastolic blood pressure showed upward trends, while high-density lipoprotein cholesterol showed no obvious trend in the TyG index at a range of 7.8-11.0. Receiver operating characteristic analysis was used to evaluate the predictive value of the TyG index, triglycerides, and fasting blood glucose for MS, and we found that the area under the TyG index curve was the largest (AUC = 0.89).

CONCLUSION

There were associations between the TyG index and MS and its components, and the TyG index is therefore of great value in the early diagnosis of MS.

Heart failure in diabetes

Heart failure and cardiovascular disorders represent the leading cause of death in diabetic patients. Here we present a systematic review of the main mechanisms underlying the development of diabetic cardiomyopathy. We also provide an excursus on the relative contribution of cardiomyocytes, fibroblasts, endothelial and smooth muscle cells to the pathophysiology of heart failure in diabetes. After having described the preclinical tools currently available to dissect the mechanisms of this complex disease, we conclude with a section on the most recent updates of the literature on clinical management.

Patent highlights February-March 2021

A snapshot of noteworthy recent developments in the patent literature of relevance to pharmaceutical and medical research and development.