Increase in MMP-2 activity in overweight and obese women is associated with menopausal status

Immunoaffinity Capillary Electrophoresis in the Era of Proteoforms, Liquid Biopsy and Preventive Medicine: A Potential Impact in the Diagnosis and Monitoring of Disease Progression

Over the years, multiple biomarkers have been used to aid in disease screening, diagnosis, prognosis, and response to therapy. As of late, protein biomarkers are gaining strength in their role for early disease diagnosis and prognosis in part due to the advancements in identification and characterization of a distinct functional pool of proteins known as proteoforms. Proteoforms are defined as all of the different molecular forms of a protein derived from a single gene caused by genetic variations, alternative spliced RNA transcripts and post-translational modifications. Monitoring the structural changes of each proteoform of a particular protein is essential to elucidate the complex molecular mechanisms that guide the course of disease. Clinical proteomics therefore holds the potential to offer further insight into disease pathology, progression, and prevention. Nevertheless, more technologically advanced diagnostic methods are needed to improve the reliability and clinical applicability of proteomics in preventive medicine. In this manuscript, we review the use of immunoaffinity capillary electrophoresis (IACE) as an emerging powerful diagnostic tool to isolate, separate, detect and characterize proteoform biomarkers obtained from liquid biopsy. IACE is an affinity capture-separation technology capable of isolating, concentrating and analyzing a wide range of biomarkers present in biological fluids. Isolation and concentration of target analytes is accomplished through binding to one or more biorecognition affinity ligands immobilized to a solid support, while separation and analysis are achieved by high-resolution capillary electrophoresis (CE) coupled to one or more detectors. IACE has the potential to generate rapid results with significant accuracy, leading to reliability and reproducibility in diagnosing and monitoring disease. Additionally, IACE has the capability of monitoring the efficacy of therapeutic agents by quantifying companion and complementary protein biomarkers. With advancements in telemedicine and artificial intelligence, the implementation of proteoform biomarker detection and analysis may significantly improve our capacity to identify medical conditions early and intervene in ways that improve health outcomes for individuals and populations.

Brain-Derived Neurotropic Factor, Vascular Endothelial Growth Factor and Matrix Metalloproteinases as Markers of Metabolic Status in Non-Growth Hormone-Treated Girls With Turner Syndrome

BACKGROUND

Turner syndrome (TS) presents a high risk of congenital heart defects and may predispose to both obesity and related metabolic complications. Hence the search for new markers as potential early predictors of the metabolic syndrome (MetS) and cardiovascular diseases appears warranted.

OBJECTIVE

To assess MMP-1 (matrix metalloproteinase-1), MMP-2 (matrix metalloproteinase-2), MMP-9 (matrix metallopeptidase-9), BDNF (brain-derived neurotrophic factor), GDNF (glial cell line-derived neurotrophic factor), and VEGF (vascular endothelial growth factor) in non-MetS TS girls not treated with growth hormone (GH) vs. healthy short stature girls, and to assess the connection with basic metabolic parameters.

METHOD

The concentrations of circulating MMP-1, MMP-2, MMP-9, BDNF, GDNF and VEGF were measured in 12 patients with TS not treated with growth hormone. The control group was composed of 17 girls with non-pathologic short stature. The patients' clinical and biochemical phenotypes were determined by weight, height, total cholesterol, HDL cholesterol, triglycerides, glucose, aminotransferases, IGF1, TSH and fT4.

RESULTS

There were no differences in mean age, weight, BMI Z-Score, or hSDS between the studied group and the controls; however, they differed in baseline values of ALT (18.2 ± 4.2 vs. 14.2 ± 4.1, p= 0.02), BDNF [29951.5 (26176.9 - 41271.9) vs. 23131.7 (18392.4 - 28313.3), p=0.01] and MMP-2 [91.8 (71.7 - 111.0) vs. 143.6 (123.7 - 244.5), p< 0.001]. BDNF correlated with ALT activity (r = 0.56 p = 0.002) and BMI Z-score (r = 0.38 p = 0.042), while MMP-2 correlated with HDL concentration (r = 0.48 p = 0.029) in all the patients. The analysis of the study group alone revealed significant positive correlations between MMP-9 and TSH (r = 0.74 p = 0.036), BDNF and both ALT (r = 0.73 p = 0.038) and TSH (r = 0.85 p = 0.008), and a negative correlation between MMP-1 and fT4 (r = -0.75 p = 0.032). The control group did not present any significant correlations.

CONCLUSION

The higher concentrations of BDNF and lower of MMP-2 found in girls with TS without MetS compared to healthy girls with short stature, could have a major impact on the future "natural" development of the metabolic status. Our findings need further studies.

Endospanin 1 Determines the Balance of Leptin-Regulated Hypothalamic Functions

Endospanin 1 (Endo1), a protein encoded in humans by the same gene than the leptin receptor (ObR), and increased by diet-induced obesity, is an important regulator of ObR trafficking and cell surface exposure, determining leptin signaling strength. Defective intracellular trafficking of the leptin receptor to the neuronal plasma membrane has been proposed as a mechanism underlying the development of leptin resistance observed in human obesity. More recently, Endo1 has emerged as a mediator of "selective leptin resistance." The underlying mechanisms of the latter are not completely understood, but the possibility of differential activation of leptin signaling pathways was suggested among others. In this respect, the expression level of Endo1 is crucial for the appropriate balance between different leptin signaling pathways and leptin functions in the hypothalamus and is likely participating in selective leptin resistance for the control of energy and glucose homeostasis.

Metalloproteinases in non-alcoholic fatty liver disease and their behavior in liver fibrosis

Non-alcoholic fatty liver disease (NAFLD) is a clinical entity of high prevalence in the world characterized by fatty infiltration of liver tissue in the absence of alcohol consumption. The natural history of the disease develops in successive phases reflected in different histological stages, with 10-20% of patients developing liver cirrhosis and fibrosis. Fibrosis is a basic connective tissue lesion defined by the increase of the fibrillary extracellular matrix (ECM) components in a tissue or organ. Matrix metalloproteinases (MMPs) constitute a family of endopeptidases, which are involved in ECM and basement membranes components degradation. Fibrogenic process is characterized by altered ECM composition, associated with modifications in MMPs behavior. The active cross-talk between adipose tissue and liver can be altered in pathologies associated to insulin resistance (IR), such as NAFLD. The role of adipokines on MMPs behavior in the liver could be partly responsible of liver damage during IR. The aim of this revision is to describe the behavior of MMPs in NAFLD and its role in the associated fibrosis.

Physical training improves visceral adipose tissue health by remodelling extracellular matrix in rats with estrogen absence: a gene expression analysis

Adipose tissue development is associated with modifications involving extracellular matrix remodelling, and metalloproteinases play a significant role in this process. Reduced circulating sexual hormones cause impacts on the size, morphology and functions of the adipose tissue, increasing susceptibility to diseases. This study investigated whether exercise training may be an alternative strategy to combat the effects promoted by estrogen decay through modulation in gene expression patterns in the extracellular matrix (ECM) of visceral adipose tissue of ovariectomized rats. Nulliparous rats (n = 40) were randomly distributed into four groups (n = 10/group): sham sedentary (Sh-S), sham resistance training (Sh-Rt), ovariectomized sedentary (Ovx-S) and ovariectomized resistance training (Ovx-Rt). The Sh-S animals did not have any type of training. The body mass and food intake, ECM gene expression, gelatinase MMP-2 activity and adipocyte area were measured. A lack of estrogen promoted an increase in body mass, food intake and the visceral, parametrial and subcutaneous adipocyte areas. The ovariectomy upregulated the expression of MMP-2, MMP-9, TGF-β, CTGF, VEGF-A and MMP-2 activity. On the other hand, resistance training decreased the body mass, food intake and the adipocyte area of the three fat depots analysed; upregulated TIMP-1, VEGF-A and MMP-2 gene expression; downregulated MMP-9, TGF-β and CTGF gene expression; and decreased the MMP-2 activity. We speculate that resistance training on a vertical ladder could play an important role in maintaining and remodelling ECM by modulation in the ECM gene expression and MMP-2 activity, avoiding its destabilization which is impaired by the lack of estrogen.

Circulating and adipose tissue matrix metalloproteinases in cardiometabolic risk environments: pathophysiological aspects

Matrix metalloproteinases (MMPs) play an important role during physiological tissue remodeling in embryonic development and angiogenesis, as well as in pathophysiological conditions such as obesity and development and vulnerability of atherosclerotic plaque. Moreover, MMP circulating levels have emerged as potential biomarkers of cardiovascular disease. MMP expression and activity are regulated by different factors such as insulin resistance and obesity. Expanded fat tissue has been demonstrated to be an active organ, where MMPs also exert a role in adipogenesis, angiogenesis, and proliferation of extracellular matrix (ECM). However, the lack of association between adipose tissue and plasma levels of some MMPs, specifically MMP-2 and MMP-9, suggests that this tissue is not a major contributor to circulating gelatinases. MMPs are also co-expressed or co-repressed in response to inflammatory adipocytokines, like adiponectin and leptin. Adiponectin may also play a protective role in plaque rupture through selectively increasing the tissue inhibitor of metalloproteinase (TIMP) expression. Leptin induces the expression of MMP-2 activators as well as the expression of MMP-2, MMP-9, and TIMP-1 in different human cells. Furthermore, sex hormones also participate in MMP regulation. In postmenopausal women, hormone replacement therapy produces an increase in MMP activity, leading to a breakdown in ECM homeostasis and accelerated progression of vascular pathologies. Besides, in men, an inverse relationship between testosterone levels and MMP-2 activity has been described. It is still necessary to go forward in the study of MMPs in different metabolic situations to corroborate their role as vulnerable plaque biomarkers.

Adiponectin predicts MMP-2 activity independently of obesity

BACKGROUND

Matrix metalloproteinases (MMPs), especially MMP-2 and MMP-9, have been identified in atherosclerotic plaques and have been directly associated with plaque remodelling and vulnerability. Cardiovascular disease (CVD) is related to insulin resistance (IR) and obesity, characterized by changes in plasma levels of inflammatory markers, such as adiponectin and C-reactive protein (CRP). Our aim was to evaluate the impact of both proteins on MMP-2 and MMP-9 behaviour in individuals with IR.

MATERIALS AND METHODS

Plasma MMP-2 and MMP-9 activity, adiponectin and hs-CRP concentration and lipoprotein profile were determined in 52 patients with metabolic syndrome (MS) and 27 controls.

RESULTS

Patients with MS presented significantly higher MMP-2 activity than controls: 0·95 ± 0·12 vs. 0·77 ± 0·15 relative units (RU) (P < 0·001), while MMP-9 activity was not detectable. MMP-2 activity decreased across quartiles of adiponectin, being significantly reduced in individuals with the highest levels of adiponectin in compared with the lowest levels (0·75 ± 0·17 vs. 0·93 ± 0·09 RU, P < 0·005). This difference persisted significant after adjusting by obesity markers. MMP-2 activity was significantly increased in individuals with the highest levels (G3) compared with those with the lowest levels (G1) of hs-CRP (0·94 ± 0·12 vs. 0·86 ± 0·12, P = 0·041) CONCLUSION: In this study, we observed that adiponectin levels predicted MMP-2 plasma activity independently of obesity. This finding suggests that the inflammatory process, associated with the highest CVD risk, would be involved in MMPs vascular production.

Proteases in cardiometabolic diseases: Pathophysiology, molecular mechanisms and clinical applications

Cardiovascular disease is the leading cause of death in the U.S. and other developed countries. Metabolic syndrome, including obesity, diabetes/insulin resistance, hypertension and dyslipidemia is a major threat for public health in the modern society. It is well established that metabolic syndrome contributes to the development of cardiovascular disease collective called as cardiometabolic disease. Despite documented studies in the research field of cardiometabolic disease, the underlying mechanisms are far from clear. Proteases are enzymes that break down proteins, many of which have been implicated in various diseases including cardiac disease. Matrix metalloproteinase (MMP), calpain, cathepsin and caspase are among the major proteases involved in cardiac remodeling. Recent studies have also implicated proteases in the pathogenesis of cardiometabolic disease. Elevated expression and activities of proteases in atherosclerosis, coronary heart disease, obesity/insulin-associated heart disease as well as hypertensive heart disease have been documented. Furthermore, transgenic animals that are deficient in or over-express proteases allow scientists to understand the causal relationship between proteases and cardiometabolic disease. Mechanistically, MMPs and cathepsins exert their effect on cardiometabolic diseases mainly through modifying the extracellular matrix. However, MMP and cathepsin are also reported to affect intracellular proteins, by which they contribute to the development of cardiometabolic diseases. On the other hand, activation of calpain and caspases has been shown to influence intracellular signaling cascade including the NF-κB and apoptosis pathways. Clinically, proteases are reported to function as biomarkers of cardiometabolic diseases. More importantly, the inhibitors of proteases are credited with beneficial cardiometabolic profile, although the exact molecular mechanisms underlying these salutary effects are still under investigation. A better understanding of the role of MMPs, cathepsins, calpains and caspases in cardiometabolic diseases process may yield novel therapeutic targets for treating or controlling these diseases. This article is part of a Special Issue entitled: Autophagy and protein quality control in cardiometabolic diseases.

Protective effect of Xin Mai Jia ultrafiltration extract on human umbilical vein endothelial cell injury induced by hydrogen peroxide and the effect on the NO-cGMP signaling pathway

The aim of the present study was to evaluate the protective effect of the ultrafiltration extract of Xin Mai Jia (XMJ) on a human umbilical vein endothelial cell (HUVEC) injury model induced by hydrogen peroxide (H₂O₂), by providing experimental data to investigate the mechanism and efficacy underlying the therapeutic effects on atherosclerosis. HUVECs were first injured by H₂O₂ and then varying final concentrations of the Chinese herb extract were added. Effects of the XMJ extract on morphology, activity, monolayer permeability, biochemical indicators, cytokines, endothelial nitric oxide synthase (eNOS) protein content and eNOS gene expression in the HUVECs were analyzed. H₂O₂ significantly promoted HUVEC injury. The XMJ ultrafiltration extract significantly improved the morphological changes in the injured HUVECs. In addition, XMJ treatment increased cell activity and decreased monolayer permeability. The expression levels of intracellular adhesion molecule-1, vascular adhesion molecule-1, interleukin-1 and -6 and nuclear factor-κB decreased, while the expression levels of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 increased with XMJ administration. Increased levels of nitric oxide (NO), eNOS protein and eNOS gene expression were also observed. Therefore, the XMJ ultrafiltration extract exhibits marked anti-inflammatory effects and antioxidant abilities. These properties significantly inhibited the H₂O₂-induced injury of HUVECs, which may be associated with the NO-cyclic guanosine monophosphate signaling pathway.

The beneficial role of vitamin D in obesity: possible genetic and cell signaling mechanisms

The prevalence rates of overweight and obesity are considered an important public issue in the United States, and both of these conditions are increasing among both children and adults. There is evidence of aberrations in the vitamin D-endocrine system in obese subjects. Vitamin D deficiency is highly prevalent in patients with obesity, and many studies have demonstrated the significant effect of calcitriol on adipocytes. Genetic studies have provided an opportunity to determine which proteins link vitamin D to obesity pathology, including the vitamin D receptor, toll-like receptors, the renin-angiotensin system, apolipoprotein E, vascular endothelial growth factor, and poly (ADP-ribose) polymerase-1. Vitamin D also exerts its effect on obesity through cell-signaling mechanisms, including matrix metalloproteinases, mitogen-activated protein kinase pathways, the reduced form of nicotinamide adenine dinucleotide phosphate, prostaglandins, reactive oxygen species, and nitric oxide synthase.

In conclusion, vitamin D may have a role in obesity. The best form of vitamin D for use in the obese individuals is calcitriol because it is the active form of the vitamin D₃ metabolite, its receptors are present in adipocytes, and modulates inflammatory cytokine expression.