Matrix metalloproteinases are differentially expressed in adipose tissue during obesity and modulate adipocyte differentiation

Modulation of adipose tissue metabolism by exosomes in obesity

Obesity and its related metabolic complications represent a significant global health challenge. Central to this is the dysregulation of glucolipid metabolism, with a predominant focus on glucose metabolic dysfunction in the current research, whereas adipose metabolism impairment garners less attention. Exosomes (EXs), small extracellular vesicles (EVs) secreted by various cells, have emerged as important mediators of intercellular communication and have the potential to be biomarkers, targets, and therapeutic tools for diverse diseases. In particular, EXs have been found to play a role in adipose metabolism by transporting cargoes such as noncoding RNAs (ncRNA), proteins, and other factors. This review article summarizes the current understanding of the role of EXs in mediating adipose metabolism disorders in obesity. It highlights their roles in adipogenesis (encompassing adipogenic differentiation and lipid synthesis), lipid catabolism, lipid transport, and white adipose browning. The insights provided by this review offer new avenues for developing exosome-based therapies to treat obesity and its associated comorbidities.

Preventing obesity, insulin resistance and type 2 diabetes by targeting MT1-MMP

Obesity is one of the predominant risk factors for type 2 diabetes. Despite all the modern advances in medicine, an effective drug treatment for obesity without overt side effects has not yet been found. The discovery of growth and differentiation factor 15 (GDF15), an appetite-regulating hormone, created hopes for the treatment of obesity. However, an insufficient understanding of the physiological regulation of GDF15 has been a major obstacle to mitigating GDF15-centric treatment of obesity. Our recent studies revealed how a series of proteolytic events predominantly mediated by membrane-type 1 matrix metalloproteinase (MT1-MMP/MMP14), a key cell-surface metalloproteinase involved in extracellular remodeling, contribute to the pathogenesis of metabolic disorders, including obesity and diabetes. The MT1-MMP-mediated cleavage of the GDNF family receptor-α-like (GFRAL), a key neuronal receptor of GDF15, controls the satiety center in the hindbrain, thereby regulating non-homeostatic appetite and bodyweight changes. Furthermore, increased activation of MT1-MMP does not only lead to increased risk of obesity, but also causes age-associated insulin resistance by cleaving Insulin Receptor in major metabolic tissues. Importantly, inhibition of MT1-MMP effectively protects against obesity and diabetes, revealing the therapeutic potential of targeting MT1-MMP for the management of metabolic disorders.

A macrophage-collagen fragment axis mediates subcutaneous adipose tissue remodeling in mice

Efficient removal of fibrillar collagen is essential for adaptive subcutaneous adipose tissue (SAT) expansion that protects against ectopic lipid deposition during weight gain. Here, we used mice to further define the mechanism for this collagenolytic process. We show that loss of collagen type-1 (CT1) and increased CT1-fragment levels in expanding SAT are associated with proliferation of resident M2-like macrophages that display increased CD206-mediated engagement in collagen endocytosis compared to chow-fed controls. Blockage of CD206 during acute high-fat diet-induced weight gain leads to SAT CT1-fragment accumulation associated with elevated inflammation and fibrosis markers. Moreover, these SAT macrophages' engagement in collagen endocytosis is diminished in obesity associated with elevated levels collagen fragments that are too short to assemble into triple helices. We show that such short fragments provoke M2-macrophage proliferation and fibroinflammatory changes in fibroblasts. In conclusion, our data delineate the importance of a macrophage-collagen fragment axis in physiological SAT expansion. Therapeutic targeting of this process may be a means to prevent pathological adipose tissue remodeling, which in turn may reduce the risk for obesity-related metabolic disorders.

Expression analysis of MMP14: Key enzyme action in modulating visceral adipose tissue plasticity in patients with obesity

Compromised adipose tissue plasticity is a hallmark finding of obesity orchestrated by the intricate interplay between various extracellular matrix components. Collagen6 (COL6) is well characterized in obese visceral adipose tissue (VAT), not much is known about MMP14 which is hypothesized to be the key player in matrix reorganization. Subjects with obesity (BMI ≥40; n = 50) aged 18-60 years undergoing bariatric surgery and their age-matched controls (BMI < 25; n = 30) were included. MMP14, Col6A3 and Tissue inhibitor of metalloproteinase 2 (TIMP2) mRNA expression was assessed in VAT and their serum levels along with endotrophin were estimated in both groups preoperatively and post-operatively in the obese group. The results were analysed statistically and correlated with anthropometric and glycaemic parameters, namely fasting glucose and insulin, HbA1c, HOMA-IR, HOMA-β and QUICKI. Circulating levels as well as mRNA expression profiling revealed significant differences between the individuals with and without obesity (p < .05), more so in individuals with diabetes and obesity (p < .05). Follow-up serum analysis revealed significantly raised MMP14 (p < .001), with decreased Col6A3, endotrophin and TIMP2 levels (p < .01, p < .001 and p < .01, respectively). A rise in serum MMP14 protein, simultaneous with post-surgical weight loss and decreased serum levels of associated extracellular matrix (ECM) remodellers, suggests its crucial role in modulating obesity-associated ECM fibrosis and pliability of VAT.

Roles of Matrix Metalloproteinases and Their Natural Inhibitors in Metabolism: Insights into Health and Disease

Matrix metalloproteinases (MMPs) are a family of zinc-activated peptidases that can be classified into six major classes, including gelatinases, collagenases, stromelysins, matrilysins, membrane type metalloproteinases, and other unclassified MMPs. The activity of MMPs is regulated by natural inhibitors called tissue inhibitors of metalloproteinases (TIMPs). MMPs are involved in a wide range of biological processes, both in normal physiological conditions and pathological states. While some of these functions occur during development, others occur in postnatal life. Although the roles of several MMPs have been extensively studied in cancer and inflammation, their function in metabolism and metabolic diseases have only recently begun to be uncovered, particularly over the last two decades. This review aims to summarize the current knowledge regarding the metabolic roles of metalloproteinases in physiology, with a strong emphasis on adipose tissue homeostasis, and to highlight the consequences of impaired or exacerbated MMP actions in the development of metabolic disorders such as obesity, fatty liver disease, and type 2 diabetes.

Characteristic and fate determination of adipose precursors during adipose tissue remodeling

Adipose tissues are essential for actively regulating systemic energy balance, glucose homeostasis, immune responses, reproduction, and longevity. Adipocytes maintain dynamic metabolic needs and possess heterogeneity in energy storage and supply. Overexpansion of adipose tissue, especially the visceral type, is a high risk for diabetes and other metabolic diseases. Changes in adipocytes, hypertrophy or hyperplasia, contribute to the remodeling of obese adipose tissues, accompanied by abundant immune cell accumulation, decreased angiogenesis, and aberrant extracellular matrix deposition. The process and mechanism of adipogenesis are well known, however, adipose precursors and their fate decision are only being defined with recent information available to decipher how adipose tissues generate, maintain, and remodel. Here, we discuss the key findings that identify adipose precursors phenotypically, with special emphasis on the intrinsic and extrinsic signals in instructing and regulating the fate of adipose precursors under pathophysiological conditions. We hope that the information in this review lead to novel therapeutic strategies to combat obesity and related metabolic diseases.

Knocking Down CDKN2A in 3D hiPSC-Derived Brown Adipose Progenitors Potentiates Differentiation, Oxidative Metabolism and Browning Process

Human induced pluripotent stem cells (hiPSCs) have the potential to be differentiated into any cell type, making them a relevant tool for therapeutic purposes such as cell-based therapies. In particular, they show great promise for obesity treatment as they represent an unlimited source of brown/beige adipose progenitors (hiPSC-BAPs). However, the low brown/beige adipocyte differentiation potential in 2D cultures represents a strong limitation for clinical use. In adipose tissue, besides its cell cycle regulator functions, the cyclin-dependent kinase inhibitor 2A (CDKN2A) locus modulates the commitment of stem cells to the brown-like type fate, mature adipocyte energy metabolism and the browning of adipose tissue. Here, using a new method of hiPSC-BAPs 3D culture, via the formation of an organoid-like structure, we silenced CDKN2A expression during hiPSC-BAP adipogenic differentiation and observed that knocking down CDKN2A potentiates adipogenesis, oxidative metabolism and the browning process, resulting in brown-like adipocytes by promoting UCP1 expression and beiging markers. Our results suggest that modulating CDKN2A levels could be relevant for hiPSC-BAPs cell-based therapies.

The impact of adipokines on vascular networks in adipose tissue

Adipose tissue (AT) is a highly active and plastic endocrine organ. It secretes numerous soluble molecules known as adipokines, which act locally to AT control the remodel and homeostasis or exert pleiotropic functions in different peripheral organs. Aberrant production or loss of certain adipokines contributes to AT dysfunction associated with metabolic disorders, including obesity. The AT plasticity is strictly related to tissue vascularization. Angiogenesis supports the AT expansion, while regression of blood vessels is associated with AT hypoxia, which in turn mediates tissue inflammation, fibrosis and metabolic dysfunction. Several adipokines can regulate endothelial cell functions and are endowed with either pro- or anti-angiogenic properties. Here we address the role of adipokines in the regulation of angiogenesis. A better understanding of the link between adipokines and angiogenesis will open the way for novel therapeutic approaches to treat obesity and metabolic diseases.

Extracellular Matrix (ECM) and Fibrosis in Adipose Tissue: Overview and Perspectives

Fibrosis in adipose tissue is a major driver of obesity-related metabolic dysregulation. It is characterized by an overaccumulation of extracellular matrix (ECM) during unhealthy expansion of adipose tissue in response to over nutrition. In obese adipose-depots, hypoxia stimulates multiple pro-fibrotic signaling pathways in different cell populations, thereby inducing the overproduction of the ECM components, including collagens, noncollagenous proteins, and additional enzymatic components of ECM synthesis. As a consequence, local fibrosis develops. The result of fibrosis-induced mechanical stress not only triggers cell necrosis and inflammation locally in adipose tissue but also leads to system-wide lipotoxicity and insulin resistance. A better understanding of the mechanisms underlying the obesity-induced fibrosis will help design therapeutic approaches to reduce or reverse the pathological changes associated with obese adipose tissue. Here, we aim to summarize the major advances in the field, which include newly identified fibrotic factors, cell populations that contribute to the fibrosis in adipose tissue, as well as novel mechanisms underlying the development of fibrosis. We further discuss the potential therapeutic strategies to target fibrosis in adipose tissue for the treatment of obesity-linked metabolic diseases and cancer. © 2023 American Physiological Society. Compr Physiol 13:4387-4407, 2023.

Supplementing Diets with Agriophyllum squarrosum Reduced Blood Lipids, Enhanced Immunity and Anti-Inflammatory Capacities, and Mediated Lipid Metabolism in Tan Lambs

Agriophyllum squarrosum (sand rice), a widespread desert plant, possesses anti-hyperglycemic and anti-inflammatory properties, and has been used in traditional Chinese medicine for many years. However, its effects on ruminants are unknown. To fill this gap, we examined the effects of A. squarrosum on the immune and anti-inflammatory responses of lambs. A total of 23, 6-month-old Tan ewe-lambs (27.6 ± 0.47 kg) were divided into four groups and offered a basic diet (C—control), or a diet that contained 10%, 20%, or 30% A. squarrosum, on a dry matter basis, for 128 days. Serum concentrations of total cholesterol were lower (p = 0.004) in the 30% supplemented lambs than controls, while concentrations of high-density lipoprotein cholesterol were lower (p = 0.006) in the 10% and 20%, but not in 30% supplemented lambs than controls. Serum-cortisol concentrations were lower (p = 0.012) in the 30% supplemented lambs and free fatty acid concentrations were higher in the 10% and 20% supplemented lambs than in control lambs (p < 0.001). Supplementation with A. squarrosum decreased (p < 0.05) the area of adipocytes in subcutaneous adipose tissue, but there was no difference between the 20% and 30% diets. Conversely, the area in visceral adipose tissue (VAT) increased (p < 0.05), especially for the 10% and 20% supplemented diets. Supplementation with A. squarrosum also enriched immune and anti-inflammatory related and lipid and glucose-metabolic pathways and associated differentially expressed gene expressions in adipose tissue. A total of 10 differential triacylglycerol, 34 differential phosphatidylcholines and seven differential phosphatidylethanolamines decreased in the diet with 30% supplementation, when compared to the other diets. Finally, adipocyte-differentiation genes, and immune and inflammatory response-related gene expression levels decreased in lamb adipocytes cultured with an aqueous A. squarrosum extract. In conclusion, supplementing lamb diets with A. squarrosum reduced blood lipids, enhanced immunity and anti-inflammatory capacities, and mediated lipid metabolism in adipose tissue and adipocytes of Tan lambs. A level of approximately 10% is recommended, but further research is required to determine the precise optimal level.

Obesity-Associated ECM Remodeling in Cancer Progression

Adipose tissue, an energy storage and endocrine organ, is emerging as an essential player for ECM remodeling. Fibrosis is one of the hallmarks of obese adipose tissue, featuring excessive ECM deposition and enhanced collagen alignment. A variety of ECM components and ECM-related enzymes are produced by adipocytes and myofibroblasts in obese adipose tissue. Data from lineage-tracing models and a single-cell analysis indicate that adipocytes can transform or de-differentiate into myofibroblast/fibroblast-like cells. This de-differentiation process has been observed under normal tissue development and pathological conditions such as cutaneous fibrosis, wound healing, and cancer development. Accumulated evidence has demonstrated that adipocyte de-differentiation and myofibroblasts/fibroblasts play crucial roles in obesity-associated ECM remodeling and cancer progression. In this review, we summarize the recent progress in obesity-related ECM remodeling, the mechanism underlying adipocyte de-differentiation, and the function of obesity-associated ECM remodeling in cancer progression.

Serum Level of MMP-3 and MMP-9 in Patients with Diabetes Mellitus Type 2 Infected with Epstein-Barr Virus

Diabetes mellitus type 2 (DM2) has recently become one of the most important health problems in the world. Patients with DM2 with long-term glycaemia are more likely to become infected than the healthy population. Matrix metalloproteinases (MMPs) play a key role in tissue remodeling during various physiological processes. However, it has been reported that certain MMPs are overexpressed during the development of various human diseases. In this study, we analyzed the levels of MMP-3 and MMP-9 in the serum of DM2 patients with and without Epstein-Barr virus (EBV) infection. The study included 115 patients with DM2 hospitalized in the Internal Ward of the Masovian Specialist Hospital in Radom, Poland, who were divided into two groups: EBV-positive and EBV-negative. The levels of MMP-3 and MMP-9 were tested in the serum of patients using the ELISA method, while the presence of EBV in saliva was tested by polymerase chain reaction (PCR). The presented studies showed a significant difference in the concentration of both MMPs in diabetic patients additionally infected with EBV compared to the group of non-infected individuals. It seems that MMPs may be useful biomarkers in the diagnosis, prognosis, and monitoring of diabetes associated with EBV infection.

Adipose Tissue Development Relies on Coordinated Extracellular Matrix Remodeling, Angiogenesis, and Adipogenesis

Despite developing prenatally, the adipose tissue is unique in its ability to undergo drastic growth even after reaching its mature size. This development and subsequent maintenance rely on the proper coordination between the vascular niche and the adipose compartment. In this review, the process of adipose tissue development is broken down to explain (1) the ultrastructural matrix remodeling that is undertaken during simultaneous adipogenesis and angiogenesis, (2) the paracrine crosstalk involved during adipose development, (3) the mechanical regulators involved in adipose growth, and (4) the proteolytic and paracrine oversight for matrix remodeling during adipose development. It is crucial to gain a better understanding of the complex relationships that exist between adipose tissue and the vasculature during tissue development to provide insights into the pathological tissue expansion of obesity and to develop improved soft-tissue reconstruction techniques.

Diastolic Dysfunction and Heart Failure With Preserved Ejection Fraction In Patients With Resistant Hypertension and Type 2 Diabetes Mellitus

Aim      To study the incidence and clinical and pathophysiological features of diastolic dysfunction (DD) and chronic heart failure with preserved ejection fraction (HFpEF) in patients with resistant arterial hypertension (RAH) associated with type 2 diabetes mellitus (DM).Material and methods  A cross-sectional study that included 36 patients with RAH associated with type 2 DM (mean age, 61.4±6.4 years; 14 men) was performed. Measurement of office and 24-h blood pressure (BP), standard echocardiography with assessment of diastolic function (DF) and ventricular-arterial coupling, doppler ultrasound imaging of renal blood flow, and laboratory tests (blood glucose, glycated hemoglobin, blood creatinine, tumor necrosis factor α (TNF-α), brain natriuretic peptide (BNP), type 2 and type 9 matrix metalloproteinases (MMP-2 and MMP-9), tissue inhibitor of MMP 1 (TIMP-1), 24-h urine protein test, and 24-h urine volume test were performed for all patients. HFpEF was diagnosed according to criteria of the American Society of Echocardiography and the European Society of Cardiology 2019, and the Russian Clinical Guidelines on Diagnosis and Treatment of CHF 2017 and 2020.Results All patients had DD. Incidence of HFpEF detection according to the Russian Guidelines 2017 was 100%; according to the Russian Guidelines 2020, that included a required increase in BNP, and according to the criteria of the European Guidelines 2019, this incidence was 89 %. In 55.6 % of patients, DD corresponded to grade 2 (pseudonormal type). According to the correlation analysis, the DF impairment was associated with increases in pulse BP, myocardial mass, arterial and left ventricular elastance (arterial wall and left ventricular elasticity), basal glycemia and DM duration, MMP-2 level, proteinuria, blood creatinine, renal vascular resistance, and also with decreases in 24-h urine volume, MMP-9, TIMP-1, and TIMP-1/MMP-2. Significance of the relations of mean E / e' ratio with nighttime pulse BP, MMP-9, and 24-h urine volume were confirmed by results of multiple linear regression analysis. Increased myocardial and vascular wall stiffness, concentrations of MMP-2 and TNF-α and reduced 24-h urine volume were associated with progressive impairment of DF.Conclusion      The combination of RAH and DM-2 is characterized by an extremely high incidence of DD that determines a great prevalence of HFpEF. The development and progression of DD in such patients are closely related with a complex of metabolic, proinflammatory and profibrotic biomarkers, increased vascular wall stiffness, pronounced left ventricular hypertrophy, and with structural and functional alterations in kidneys.

ZDF fa/fa rats show increasing heterogeneity in main parameters during ageing as confirmed by biometrics, oxidative stress markers and MMP activity

NEW FINDINGS

What is the central question of this study? To characterize ZDF fa/fa rats and two controls (Wistar and lean ZDF fa/+) during ageing. What is the main finding and its importance? ZDF fa/fa rats with lower glycaemia have a greater body and left ventricular weight, and lower plasma gelatinase activity compared with hyperglycaemic rats. As diabetes represents a heterogeneous metabolic disorder, the inhomogeneity of ZDF fa/fa rats may be beneficial in the study of its different aspects. Our experiments may promote a discussion regarding the suitable normoglycemic control for aged ZDF fa/fa rats, especially in experiments focused on myocardial tissue.

ABSTRACT

Zucker diabetic fatty rats (ZDF fa/fa) - an animal model for the study of type 2 diabetes (T2D), are considered as a uniform group in most experimental studies; however, there are indices regarding their growing inhomogeneity over time. The main objective of our study was to monitor particular biometric and biochemical parameters of ZDF fa/fa rats during development to T2D and compare them with two controls (Wistar and lean ZDF fa/+). According to fasting glycaemia, ZDF fa/fa were arbitrarily split into two phenotypes - obese ZDF (fa/fa)-FAT and diabetic ZDF (fa/fa)-DIA. Glycaemia was progressively rising only in ZDF (fa/fa)-DIA which also exhibited higher cholesterol levels compared with ZDF (fa/fa)-FAT. In addition, ZDF (fa/fa)-FAT revealed more pronounced left ventricular hypertrophy and greater body weight, differentiating them from ZDF (fa/fa)-DIA. Moreover, we investigated the activity of matrix metalloproteinases (MMPs), multifunctional enzymes involved in tissue remodelling. Rats in the ZDF (fa/fa)-FAT group revealed lower plasma MMP-2 and MMP-9 activity compared with ZDF (fa/fa)-DIA. However, increased myocardial MMP-2 activity indicated left ventricular remodelling in both ZDF phenotypes. As T2D in humans represents a heterogeneous metabolic disorder, the heterogeneity of ZDF fa/fa rats may be beneficial in the study of different aspects of this pathology. Moreover, Wistar rats could serve as a more appropriate control for aged ZDF fa/fa rats than commonly used fa/+ rats that showed an increase in left ventricular weight, carbonyl stress markers in the left myocardium and MMP-2 activity in both ventricles, indicating heart remodelling processes compared with the Wistar control group. This article is protected by copyright. All rights reserved.

Importance of the Microenvironment and Mechanosensing in Adipose Tissue Biology

The expansion of adipose tissue is an adaptive mechanism that increases nutrient buffering capacity in response to an overall positive energy balance. Over the course of expansion, the adipose microenvironment undergoes continual remodeling to maintain its structural and functional integrity. However, in the long run, adipose tissue remodeling, typically characterized by adipocyte hypertrophy, immune cells infiltration, fibrosis and changes in vascular architecture, generates mechanical stress on adipose cells. This mechanical stimulus is then transduced into a biochemical signal that alters adipose function through mechanotransduction. In this review, we describe the physical changes occurring during adipose tissue remodeling, and how they regulate adipose cell physiology and promote obesity-associated dysfunction in adipose tissue.

Adipose Tissue Extracellular Matrix Remodeling in Response to Dietary Patterns and Exercise: Molecular Landscape, Mechanistic Insights, and Therapeutic Approaches

Simple Summary

Adipose tissue is considered a metabolic organ that adjusts overall energy homeostasis and critical hormones to the body’s needs. In conditions of caloric intake surpassing energy expenditure, lipid accumulation occurs with constant extracellular matrix deposition. Excess lipids and adipocyte hypertrophy may reduce extracellular matrix flexibility in conjunction with hypoxia and inflammation. These processes induce the development of adipose tissue fibrosis and correlated metabolic dysfunctions, such as insulin resistance. With the increasing rate of chronic diseases worldwide, it is essential to generate a more precise knowledge of fibrotic processes, as well as to create optimal models to study potential therapies to combat the harmful effects of extracellular matrix deposition. In this work, we focused on the physiological processes in the remodeling of adipose tissue fibrosis, along with their relevance to clinical indications. Furthermore, we emphasize understanding how lifestyle can alleviate adipocyte dysfunction. Several studies showed that a nutritionally balanced diet combined with exercise is a remarkable potential strategy for lipolytic activity, preventing rapid extracellular matrix expansion in parallel with insulin and glucose action improvements. Thus, the emerging beneficial role of exercise training and low-calorie diet on adipose tissue ECM remodeling is a topic that deserves attention from health professionals.

Abstract

The extracellular matrix (ECM) is a 3-dimensional network of molecules that play a central role in differentiation, migration, and survival for maintaining normal homeostasis. It seems that ECM remodeling is required for adipose tissue expansion. Despite evidence indicating that ECM is an essential component of tissue physiology, adipose tissue ECM has received limited attention. Hence, there is great interest in approaches to neutralize the harmful effects of ECM enlargement. This review compiles and discusses the current literature on adipose tissue ECM remodeling in response to different dietary patterns and exercise training. High-calorie diets result in substantial adipose tissue ECM remodeling, which in turn could lead to fibrosis (excess deposition of collagens, elastin, and fibronectin), inflammation, and the onset of metabolic dysfunction. However, combining a nutritionally balanced diet with exercise is a remarkable potential strategy for lipolytic activity, preventing rapid ECM expansion in different adipose tissue depots. Despite the distinct exercise modalities (aerobic or resistance exercise) reversing adipose tissue fibrosis in animal models, the beneficial effect on humans remains controversial. Defining molecular pathways and specific mechanisms that mediate the positive effects on adipose tissue, ECM is essential in developing optimized interventions to improve health and clinical outcomes.

Improved tenderness of beef from bulls supplemented with active dry yeast is related to matrix metalloproteinases and reduced oxidative stress

Supplementing diets with active dry yeast (ADY, Saccharomyces cerevisiae) improves the carcass quality grade of beef cattle and the tenderness of beef. The relevant mechanisms have not been fully elucidated, but may be related to the effect of ADY on oxidative stress and the activity of matrix metalloproteinases (MMPs). To provide further insight into these mechanisms, this study evaluated the influence of ADY supplementation on growth performance, carcass traits, meat quality, concentrations of MMPs in serum (MMP-2, MMP-9 and MMP-13), oxidative stress indices and antioxidant capacity indices in beef cattle. Forty-six crossbred Simmental × Yanbian bulls (∼18 months of age, BW 436 ± 35 kg) participated in a 145-day finishing trial. ADY supplementation significantly improved marbling deposition, intramuscular fat content, and beef tenderness (P < 0.05); altered individual fatty acid proportions in the beef and increased saturated fatty acids while decreasing polyunsaturated fatty acids (P < 0.05); significantly decreased the abundance of reactive oxygen species in serum and meat; significantly increased the level of superoxide dismutase in meat (P < 0.05); tended to increase the level of catalase (P = 0.075) in serum and glutathione reductase (P = 0.066) in meat; and increased the secretion of MMPs. The improvement of beef tenderness following ADY supplementation of finishing bulls is related to the effects of ADY on the secretion of MMPs and the lowering of oxidative stress.

Distinct Adipogenic and Fibrogenic Differentiation Capacities of Mesenchymal Stromal Cells from Pancreas and White Adipose Tissue

Pancreatic steatosis associates with β-cell failure and may participate in the development of type-2-diabetes. Our previous studies have shown that diabetes-susceptible mice accumulate more adipocytes in the pancreas than diabetes-resistant mice. In addition, we have demonstrated that the co-culture of pancreatic islets and adipocytes affect insulin secretion. The aim of this current study was to elucidate if and to what extent pancreas-resident mesenchymal stromal cells (MSCs) with adipogenic progenitor potential differ from the corresponding stromal-type cells of the inguinal white adipose tissue (iWAT). miRNA (miRNome) and mRNA expression (transcriptome) analyses of MSCs isolated by flow cytometry of both tissues revealed 121 differentially expressed miRNAs and 1227 differentially expressed genes (DEGs). Target prediction analysis estimated 510 DEGs to be regulated by 58 differentially expressed miRNAs. Pathway analyses of DEGs and miRNA target genes showed unique transcriptional and miRNA signatures in pancreas (pMSCs) and iWAT MSCs (iwatMSCs), for instance fibrogenic and adipogenic differentiation, respectively. Accordingly, iwatMSCs revealed a higher adipogenic lineage commitment, whereas pMSCs showed an elevated fibrogenesis. As a low degree of adipogenesis was also observed in pMSCs of diabetes-susceptible mice, we conclude that the development of pancreatic steatosis has to be induced by other factors not related to cell-autonomous transcriptomic changes and miRNA-based signals.

M1 Polarized Macrophages Persist in Skin of Post-Bariatric Patients after 2 Years

BACKGROUND

Obesity is considered a condition of systemic chronic inflammation. Under this condition, adipose tissue macrophages switch from an M2 (anti-inflammatory) activation pattern to an M1 (proinflammatory) activation pattern.

OBJECTIVE

The study aimed to verify the profile of skin macrophage activation after bariatric surgery as well as the role of MMP-1 in extracellular tissue remodeling.

METHODS

This is a prospective, controlled and comparative study with 20 individuals split into two groups according to their skin condition: post-bariatric and eutrophic patients. Histological and morphometric analyses based on hematoxylin-eosin, picrosirius red (collagen), orcein (elastic fiber systems), and alcian blue (mast cells)-stained sections and immunohistochemical analysis (CD68, iNOS, and mannose receptor) for macrophages and metalloproteinase-1 were performed.

RESULTS

Post-bariatric skin showed an increase in inflammation, angiogenesis, CD68, M1 macrophages (P< 0.001), and mast cells (P< 0.01); a decrease in M2 macrophages (P< 0.01); and a significant decrease in the collagen fiber network (P< 0.001). MMP-1 was increased in the papillary dermis of post-bariatric skin and decreased in the epidermis compared to eutrophic skin (P< 0.05).

CONCLUSION

This study shows that post-bariatric skin maintains inflammatory characteristics for two years. Mast cells and M1 macrophages maintain and enhance the remodeling of the dermal extracellular matrix initiated during obesity in part due to the presence of MMP-1 in the papillary dermis.

EBM LEVEL IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Obesity-related kidney disease: Beyond hypertension and insulin-resistance

Chronic kidney disease (CKD) causes considerable morbidity, mortality, and health expenditures worldwide. Obesity is a significant risk factor for CKD development, partially explained by the high prevalence of diabetes mellitus and hypertension in obese patients. However, adipocytes also possess potent endocrine functions, secreting a myriad of cytokines and adipokines that contribute to insulin resistance and induce a chronic low-grade inflammatory state thereby damaging the kidney. CKD development itself is associated with various metabolic alterations that exacerbate adipose tissue dysfunction and insulin resistance. This adipose-renal axis is a major focus of current research, given the rising incidence of CKD and obesity. Cellular senescence is a biologic hallmark of aging, and age is another significant risk factor for obesity and CKD. An elevated senescent cell burden in adipose tissue predicts renal dysfunction in animal models, and senotherapies may alleviate these phenotypes. In this review, we discuss the direct mechanisms by which adipose tissue contributes to CKD development, emphasizing the potential clinical importance of such pathways in augmenting the care of CKD.

Local Biomarkers Involved in the Interplay between Obesity and Breast Cancer

Simple Summary

Breast cancer is the second most common cancer in women worldwide. The risk of developing breast cancer depends on various mechanisms, such as age, heredity, reproductive factors, physical inactivity, and obesity. Obesity increases the risk of breast cancer and worsens outcomes for breast cancer patients. The rate of obesity is increasing worldwide, stressing the need for awareness of the association between obesity and breast cancer. In this review, we outline the biomarkers—including cellular and soluble factors—in the breast, associated with obesity, that affect the risk of breast cancer and breast cancer prognosis. Through these biomarkers, we aim to better identify patients with obesity with a higher risk of breast cancer and an inferior prognosis.

Abstract

Obesity is associated with an increased risk of breast cancer, which is the most common cancer in women worldwide (excluding non-melanoma skin cancer). Furthermore, breast cancer patients with obesity have an impaired prognosis. Adipose tissue is abundant in the breast. Therefore, breast cancer develops in an adipose-rich environment. During obesity, changes in the local environment in the breast occur which are associated with breast cancer. A shift towards a pro-inflammatory state is seen, resulting in altered levels of cytokines and immune cells. Levels of adipokines, such as leptin, adiponectin, and resistin, are changed. Aromatase activity rises, resulting in higher levels of potent estrogen in the breast. Lastly, remodeling of the extracellular matrix takes place. In this review, we address the current knowledge on the changes in the breast adipose tissue in obesity associated with breast cancer initiation and progression. We aim to identify obesity-associated biomarkers in the breast involved in the interplay between obesity and breast cancer. Hereby, we can improve identification of women with obesity with an increased risk of breast cancer and an impaired prognosis. Studies investigating mammary adipocytes and breast adipose tissue in women with obesity versus women without obesity are, however, sparse and further research is needed.

Adipocyte-derived exosomes may promote breast cancer progression in type 2 diabetes

Obesity and metabolic diseases, such as insulin resistance and type 2 diabetes (T2D), are associated with metastatic breast cancer in postmenopausal women. Here, we investigated the critical cellular and molecular factors behind this link. We found that primary human adipocytes shed extracellular vesicles, specifically exosomes, that induced the expression of genes associated with epithelial-to-mesenchymal transition (EMT) and cancer stem–like cell (CSC) traits in cocultured breast cancer cell lines. Transcription of these genes was further increased in cells exposed to exosomes shed from T2D patient–derived adipocytes or insulin-resistant adipocytes and required the epigenetic reader proteins BRD2 and BRD4 in recipient cells. The thrombospondin family protein TSP5, which is associated with cancer, was more abundant in exosomes from T2D or insulin-resistant adipocytes and partially contributed to EMT in recipient cells. Bioinformatic analysis of breast cancer patient tissue showed that greater coexpression of COMP (which encodes TSP5) and BRD2 or BRD3 correlated with poorer prognosis, specifically decreased distant metastasis–free survival. Our findings reveal a mechanism of exosome-mediated cross-talk between metabolically abnormal adipocytes and breast cancer cells that may promote tumor aggressiveness in patients with T2D.

Metalloproteinases in Endometrial Cancer-Are They Worth Measuring?

Endometrial cancer is one of the most common gynecological malignancies, yet the molecular mechanisms that lead to tumor development and progression are still not fully established. Matrix metalloproteinases (MMPs) are a group of enzymes that play an important role in carcinogenesis. They are proteases involved in the degradation of the extracellular matrix (ECM) that surrounds the tumor and the affected tissue allows cell detachment from the primary tumor causing local invasion and metastasis formation. Recent investigations demonstrate significantly increased metalloproteinase and metalloproteinase inhibitor levels in patients with endometrial cancer compared to those with normal endometrium. In this review, we aim to show their clinical significance and possible use in the diagnosis and treatment of patients with endometrial cancer. We have critically summarized and reviewed the research on the role of MMPs in endometrial cancer.

The Mannose Receptor: From Endocytic Receptor and Biomarker to Regulator of (Meta)Inflammation

The mannose receptor is a member of the C-type lectin (CLEC) family, which can bind and internalize a variety of endogenous and pathogen-associated ligands. Because of these properties, its role in endocytosis as well as antigen processing and presentation has been studied intensively. Recently, it became clear that the mannose receptor can directly influence the activation of various immune cells. Cell-bound mannose receptor expressed by antigen-presenting cells was indeed shown to drive activated T cells towards a tolerogenic phenotype. On the other hand, serum concentrations of a soluble form of the mannose receptor have been reported to be increased in patients suffering from a variety of inflammatory diseases and to correlate with severity of disease. Interestingly, we recently demonstrated that the soluble mannose receptor directly promotes macrophage proinflammatory activation and trigger metaflammation. In this review, we highlight the role of the mannose receptor and other CLECs in regulating the activation of immune cells and in shaping inflammatory responses.

MMPs and TIMPs levels are correlated with anthropometric parameters, blood pressure, and endothelial function in obesity

The association between matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinases (TIMPs) and obesity as well as obesity-related disease including metabolic syndrome is not fully explored. Our aims are that: (i) to evaluate the plasma levels of MMP-1, MMP-2, MMP-3, MMP-9, TIMP-1, TIMP-2 and their ratios in non-obese people, overweight and obese people with or without metabolic syndrome, (ii) to investigate correlations between MMPs or TIMPs levels and several anthropometric parameters, blood pressure, endothelial function. Anthropometric and biochemical parameters were determined in 479 randomly selected participants, subdividing according to body mass index (BMI) and metabolic syndrome status. Plasma MMPs and TIMPs levels were measured. The assessment of endothelial function was characterized in people with obesity, overweight and non-obese, using laser Doppler Flowmetry. Obese people have elevated MMP-1, MMP-2, TIMP-1, TIMP-2 levels and decreased MMP-3/TIMP-1 and MMP-9/TIMP-1 ratios compared with non-obese people. MMP-1 levels and MMP-1/TIMP-1 ratio were positively correlated with BMI and waist circumference (WC) while MMP-2 levels were negatively correlated with BMI and WC values in obese people. MMP-3 levels and MMP-3/TIMP-1 ratio were positively correlated with systolic blood pressure (SBP) or diastolic blood pressure (DBP) in obese and metabolic syndrome people. Additionally, MMP-9 levels and MMP-9/TIMP-1 ratio were negatively correlated with endothelium-dependent response in obese and metabolic syndrome people. MMP-1, MMP-2, TIMP-1, TIMP-2 levels were increased in obese subjects. Significant correlations between anthropometric parameters and MMP-1 as well as MMP-1/TIMP-1 ratio supported these results. MMP-3 and -9 levels as well as their ratios with TIMP-1 were associated with blood pressure and endothelial-dependent response, respectively. In conclusion, our results demonstrated that MMP-1, MMP-3 and MMP-9 levels were correlated with several obesity-related parameters including BMI, WC, blood pressure and endothelial-dependent response. Our findings will hopefully provide new aspects for the use of MMPs and TIMPs as clinical biomarkers in obesity-related cardiovascular diseases such as metabolic syndrome and hypertension. The lack of measure of MMPs activity in plasma and relevant organs/tissues in obesity and metabolic syndrome is considered as a limitation in this report.

Vitamin D Levels Correlate with Metabolic Syndrome Criteria in Algerian Patients: The Ex-vivo Immunomodulatory Effect of α, 25 Dihydroxyvitamin D3

BACKGROUND

Metabolic syndrome (MetS) is a combination of metabolic disorders with increased risks for several diseases, such as cardiovascular diseases and diabetes. It is associated with the presence of various inflammatory molecules. Vitamin D plays an important role in the regulation of metabolism homeostasis.

OBJECTIVE

The main goal of this work is to investigate vitamin D levels among Algerian MetS patients and its possible outcomes on key molecules of the immune response, as well, the immunomodulatory effects of its active metabolite.

METHODS

We evaluated vitamin D status by the electrochemiluminescence method, Nitric Oxide (NO) levels by the Griess method and Matrix Metalloproteinases (MMPs) activities such as MMP-2 and MMP-9 by zymography in plasma of patients and healthy controls (HC). The immunomodulatory effects of the active metabolite of vitamin D (α-25 (OH)2D3) on the production of NO, IL-6, IL-10, TGF- β and s-CTLA-4 were assessed by Griess method and ELISA, in peripheral blood mononuclear cells (PBMCs) of Algerian MetS patients and HC. MMPs activities were also determined ex-vivo, while iNOS expression was assessed by immunofluorescence staining.

RESULTS

Severe vitamin D deficiency was registered in Algerian MetS patients. The deficiency was found to be associated with an elevated in vivo NO production and high MMPs activity. Interestingly, α-25 (OH)2D3 declined the NO/iNOS system and IL-6 production, as well as MMPs activities. However, the ex-vivo production of IL-10, TGF-β increased in response to the treatment. We observed in the same way, the implication of s-CTLA-4 in MetS, which was markedly up-regulated with α-25 (OH)2D3.

CONCLUSION

Our report indicated the relationship between MetS factors and Vitamin D deficiency. The ex-vivo findings emphasize its impact on maintaining regulated immune balance.

Membrane-type I matrix metalloproteinase (MT1-MMP), lipid metabolism and therapeutic implications

Lipids exert many essential physiological functions, such as serving as a structural component of biological membranes, storing energy, and regulating cell signal transduction. Dysregulation of lipid metabolism can lead to dyslipidemia related to various human diseases, such as obesity, diabetes, and cardiovascular disease. Therefore, lipid metabolism is strictly regulated through multiple mechanisms at different levels, including the extracellular matrix. Membrane-type I matrix metalloproteinase (MT1-MMP), a zinc-dependent endopeptidase, proteolytically cleaves extracellular matrix components, and non-matrix proteins, thereby regulating many physiological and pathophysiological processes. Emerging evidence supports the vital role of MT1-MMP in lipid metabolism. For example, MT1-MMP mediates ectodomain shedding of low-density lipoprotein receptor and increases plasma low-density lipoprotein cholesterol levels and the development of atherosclerosis. It also increases the vulnerability of atherosclerotic plaque by promoting collagen cleavage. Furthermore, it can cleave the extracellular matrix of adipocytes, affecting adipogenesis and the development of obesity. Therefore, the activity of MT1-MMP is strictly regulated by multiple mechanisms, such as autocatalytic cleavage, endocytosis and exocytosis, and post-translational modifications. Here, we summarize the latest advances in MT1-MMP, mainly focusing on its role in lipid metabolism, the molecular mechanisms regulating the function and expression of MT1-MMP, and their pharmacotherapeutic implications.

Matrix Metalloproteinase 3: A Promoting and Destabilizing Factor in the Pathogenesis of Disease and Cell Differentiation

Cells must alter their expression profiles and morphological characteristics but also reshape the extracellular matrix (ECM) to fulfill their functions throughout their lifespan. Matrix metalloproteinase 3 (MMP-3) is a member of the matrix metalloproteinase (MMP) family, which can degrade multiple ECM components. MMP-3 can activate multiple pro-MMPs and thus initiates the MMP-mediated degradation reactions. In this review, we summarized the function of MMP-3 and discussed its effects on biological activities. From this point of view, we emphasized the positive and negative roles of MMP-3 in the pathogenesis of disease and cell differentiation, highlighting that MMP-3 is especially closely involved in the occurrence and development of osteoarthritis. Then, we discussed some pathways that were shown to regulate MMP-3. By writing this review, we hope to provide new topics of interest for researchers and attract more researchers to investigate MMP-3.

A Metalloproteinase Induces an Inflammatory Response in Preadipocytes with the Activation of COX Signalling Pathways and Participation of Endogenous Phospholipases A2

Matrix metalloproteinases (MMPs) are proteolytic enzymes that have been associated with the pathogenesis of inflammatory diseases and obesity. Adipose tissue in turn is an active endocrine organ capable of secreting a range of proinflammatory mediators with autocrine and paracrine properties, which contribute to the inflammation of adipose tissue and adjacent tissues. However, the potential inflammatory effects of MMPs in adipose tissue cells are still unknown. This study investigates the effects of BmooMPα-I, a single-domain snake venom metalloproteinase (SVMP), in activating an inflammatory response by 3T3-L1 preadipocytes in culture, focusing on prostaglandins (PGs), cytokines, and adipocytokines biosynthesis and mechanisms involved in prostaglandin E₂ (PGE₂) release. The results show that BmooMPα-I induced the release of PGE₂, prostaglandin I₂ (PGI₂), monocyte chemoattractant protein-1 (MCP-1), and adiponectin by preadipocytes. BmooMPα-I-induced PGE₂ biosynthesis was dependent on group-IIA-secreted phospholipase A₂ (sPLA₂-IIA), cytosolic phospholipase A₂-α (cPLA₂-α), and cyclooxygenase (COX)-1 and -2 pathways. Moreover, BmooMPα-I upregulated COX-2 protein expression but not microsomal prostaglandin E synthase-1 (mPGES-1) expression. In addition, we demonstrate that the enzymatic activity of BmooMPα-I is essential for the activation of prostanoid synthesis pathways in preadipocytes. These data highlight preadipocytes as important targets for metalloproteinases and provide new insights into the contribution of these enzymes to the inflammation of adipose tissue and tissues adjacent to it.

Serum MMP-3 and its association with central arterial stiffness among young adults is moderated by smoking and BMI

Central arterial stiffness is an independent predictor of cardiovascular disease. It is characterized by a marked reduction in the elastin-collagen ratio of the arterial wall extracellular matrix (ECM), and is largely the result of degradation of various ECM components. Matrix metalloproteinase-3 (MMP-3) may contribute to central arterial stiffness via its involvement in ECM homeostasis and remodeling. This study examined the association between serum MMP-3 concentrations and central arterial stiffness and potential interactions of MMP-3 and traditional cardiovascular risk factors in a population of healthy young adults. A total of 206 participants (n = 109 females) aged 19-25 years were included in the current study. Central arterial stiffness was measured non-invasively as carotid-femoral pulse wave velocity (cfPWV) (m/s). MMP-3 concentrations (ng/ml) were measured using ELISA techniques. Regression analyses were used to examine the association between cfPWV and MMP-3, adjusting for age, sex, smoking status, body mass index (BMI), instantaneous mean arterial pressure (MAP) and heart rate, and serum C-reactive protein. Interactions between MMP-3 with smoking, BMI, sex, and MAP were analyzed in subsequent regression models. MMP-3 was an independent predictor of cfPWV (β = 0.187, p = 0.007), and significant interactions between MMP-3 and regular smoking (β = 0.291, p = 0.022), and MMP-3 and BMI (β = 0.210, p = 0.013) were observed. Higher serum MMP-3 concentrations were associated with a faster cfPWV and thus, greater central arterial stiffness. Interactions between MMP-3 and smoking, and MMP-3 and BMI may, in part, drive the association between MMP-3 and central arterial stiffness.

Markers of tissue remodeling and inflammation in the white and brown adipose tissues of a model hibernator

The thirteen-lined ground squirrel is a model fat-storing hibernator that nearly doubles its weight in the fall to fuel metabolism with triglycerides throughout the winter months. Hibernator brown and white adipose tissue (BAT, WAT) are important to study in terms of their inflammatory profile and tissue remodeling mechanisms since controlled and natural regulation of these processes could inform new pharmacological interventions that limit oxidative stress and inflammation in the adipose tissues of humans suffering from obesity, promote non-shivering thermogenesis-mediated weight loss, or prevent tissue damage in transplantable organs emerging from cold-storage. Thus, markers of inflammation like cytokines and soluble receptors and tissue remodeling proteins such as matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) were investigated in normothermic, torpid, and arousing ground squirrels. Multiplex protein assays and western blotting revealed fewer changes in WAT compared to BAT. Pro-inflammatory IL-1α levels increased during torpor and soluble epidermal growth factor receptor protein levels increased during arousal in BAT. Given their known roles in other model systems, these proteins could regulate processes like adipogenesis, lipid catabolism, or cell motility. Decreased TIMP2 levels combined with maintained MMP2 or MMP3 protein levels suggested that BAT may avoid tissue remodeling until arousal. No changes in WAT inflammatory cytokines or soluble receptors as well as decreased MMP2 levels during torpor and arousal suggested inflammation and modification to the extracellular matrix is likely suppressed in WAT. This study emphasizes the fat-but-fit nature of the hibernating ground squirrel and the ability of its fat stores to suppress inflammation.

Effects of quercetin on cell differentiation and adipogenesis in 3T3-L1 adipocytes

BACKGROUND/OBJECTIVES

Adipocytes undergo angiogenesis to receive nutrients and oxygen needed for adipocyte' growth and differentiation. No study relating quercetin with angiogenesis in adipocytes exists. Therefore, this study investigated the role of quercetin on adipogenesis in 3T3-L1 cells, acting through matrix metalloproteinases (MMPs).

MATERIALS/METHODS

After proliferating preadipocytes into adipocytes, various quercetin concentrations were added to adipocytes, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were performed to evaluate cell proliferation. Glycerol-3-phosphate dehydrogenase (GPDH) activity was investigated as an indicator of fat accumulation. The mRNA expressions of transcription factors related to adipocyte differentiation, CCAAT/enhancer-binding proteins (C/EBPs), peroxisomal proliferator-activated receptors (PPAR)-γ, and adipocyte protein 2 (aP2), were investigated. The mRNA expressions of proteins related to angiogenesis, vascular endothelial growth factor (VEGF)-α, vascular endothelial growth factor receptor (VEGFR)-2, MMP-2, and MMP-9, were investigated. Enzyme activities and concentrations of MMP-2 and MMP-9 were also measured.

RESULTS

Quercetin treatment suppressed fat accumulation and the expressions of adipocyte differentiation-related genes (C/EBPα, C/EBPβ, PPAR-γ, and aP2) in a concentration-dependent manner in 3T3-L1 cells. Quercetin treatments reduced the mRNA expressions of VEGF-α, VEGFR-2, MMP-2, and MMP-9 in 3T3-L1 cells. The activities and concentrations of MMP-2 and MMP-9 were also decreased significantly as the concentration of quercetin increased.

CONCLUSIONS

The results confirm that quercetin inhibits adipose tissue differentiation and fat accumulation in 3T3-L1 cells, which could occur through inhibition of the angiogenesis process related to MMPs.

Stromal Cells Present in the Melanoma Niche Affect Tumor Invasiveness and Its Resistance to Therapy

Malignant melanoma is a highly metastatic type of cancer, which arises frequently from transformed pigment cells and melanocytes as a result of long-term UV radiation exposure. In recent years, the incidence of newly diagnosed melanoma patients reached 5% of all cancer cases. Despite the development of novel targeted therapies directed against melanoma-specific markers, patients' response to treatment is often weak or short-term due to a rapid acquisition of drug resistance. Among the factors affecting therapy effectiveness, elements of the tumor microenvironment play a major role. Melanoma niche encompasses adjacent cells, such as keratinocytes, cancer-associated fibroblasts (CAFs), adipocytes, and immune cells, as well as components of the extracellular matrix and tumor-specific physicochemical properties. In this review, we summarize the current knowledge concerning the influence of cancer-associated cells (keratinocytes, CAFs, adipocytes) on the process of melanomagenesis, tumor progression, invasiveness, and the emergence of drug resistance in melanoma. We also address how melanoma can alter the differentiation and activation status of cells present in the tumor microenvironment. Understanding these complex interactions between malignant and cancer-associated cells could improve the development of effective antitumor therapeutic strategies.

Differential Expression of MMP2 and TIMP2 in Peripheral Blood Mononuclear Cells After Roux-en-Y Gastric Bypass

Matrix metalloproteinases (MMP) and their endogenous inhibitor, the tissue inhibitor of metalloproteinases (TIMP), are expressed in many different cell types and play an important role in physiologic and pathological degradation of extracellular matrix (ECM). Starting from these observations and considering the activation state of peripheral blood mononuclear cells (PBMCs) in obesity, we investigated the gene expression of metalloproteinases before and after Roux-en-Y gastric bypass (RYBG). The study was performed in the Ribeirão Preto Medical School University Hospital. Seventy-three women were divided into a study group (SG), composed of 53 individuals with severe obesity before and after 6 months of RYGB, and a control group (CG), composed of 20 normal-weight individuals. Anthropometric and body composition data were collected, and peripheral blood for ribonucleic acid (RNA) extraction. The biological samples were submitted to a quantitative real-time polymerase chain reaction to evaluate the expression of MMP2 and TIMP2 genes. Alterations in weight loss, body mass index (BMI), and fat mass (FM) were observed after 6 months of RYGB (p < 0.05). A reduction of gene expression of TIMP2 was observed after 6 months of RYGB, contributing positively to the weight loss (R ² = 0.33 p = 0.04). The enrichment analyses highlighted the interaction between TIMP2 and MMP2 genes and the molecular pathways involving the ECM remodeling in the obesity condition. RYGB contributes significantly to weight loss, improved BMI, reduced FM, and reduced TIMP2 expression in PBMCs, which might contribute to the ECM remodeling in the obesity and could be useful as a circulating biomarker.

Obesity-linked circular RNA circTshz2-2 regulates the neuronal cell cycle and spatial memory in the brain

Metabolic syndromes, including obesity, cause neuropathophysiological changes in the brain, resulting in cognitive deficits. Only a few studies explored the contribution of non-coding genes in these pathophysiologies. Recently, we identified obesity-linked circular RNAs (circRNA) by analyzing the brain cortices of high-fat-fed obese mice. In this study, we scrutinized a conserved and neuron-specific circRNA, circTshz2-2, which affects neuronal cell cycle and spatial memory in the brain. Transcriptomic and cellular analysis indicated that circTshz2-2 dysregulation altered the expression of cell division-related genes and induced cell cycle arrest at the G2/M phase of the neuron. We found that circTshz2-2 bound to the YY1 transcriptional complex and suppressed Bdnf transcription. Suppression of circTshz2-2 increased BDNF expression and reduced G2/M checkpoint proteins such as Cyclin B2 and CDK1 through BDNF/TrkB signaling pathway, resulting in cell cycle arrest and neurite elongation. Inversely, overexpression of circTshz2-2 decreased BDNF expression, induced cell cycle proteins, and shortened the neurite length, indicating that circTshz2-2 regulates neuronal cell cycle and structure. Finally, we showed that circTshz2-2 affects spatial memory in wild-type and obese mice. Our data have revealed potential regulatory roles of obesity-related circTshz2-2 on the neuronal cell cycle and memory function providing a novel link between metabolic syndromes and cognitive deficits.

Effects of BMP7 produced by group 2 innate lymphoid cells on adipogenesis

Group 2 innate lymphoid cells (ILC2s) are type 2 cytokine-producing cells that have important roles in helminth infection and allergic inflammation. ILC2s are tissue-resident cells, and their phenotypes and roles are regulated by tissue-specific environmental factors. While the role of ILC2s in the lung, intestine and bone marrow has been elucidated in many studies, their role in adipose tissues is still unclear. Here, we report on the role of ILC2-derived bone morphogenetic protein 7 (BMP7) in adipocyte differentiation and lipid accumulation. Co-culture of fat-derived ILC2s with pluripotent mesenchymal C3H10T1/2 cells and committed white preadipocyte 3T3-L1 cells resulted in their differentiation to adipocytes and induced lipid accumulation. Co-culture experiments using BMP7-deficient ILC2s revealed that BMP7, produced by ILC2s, induces differentiation into brown adipocytes. Our results demonstrate that BMP7, produced by ILC2s, affects adipocyte differentiation, particularly in brown adipocytes.

The Roles of Matrix Metalloproteinases and Their Inhibitors in Human Diseases

Matrix metalloproteinases (MMPs) are a family of zinc-dependent extracellular matrix (ECM) remodeling endopeptidases that have the capacity to degrade almost every component of the ECM. The degradation of the ECM is of great importance, since it is related to embryonic development and angiogenesis. It is also involved in cell repair and the remodeling of tissues. When the expression of MMPs is altered, it can generate the abnormal degradation of the ECM. This is the initial cause of the development of chronic degenerative diseases and vascular complications generated by diabetes. In addition, this process has an association with neurodegeneration and cancer progression. Within the ECM, the tissue inhibitors of MMPs (TIMPs) inhibit the proteolytic activity of MMPs. TIMPs are important regulators of ECM turnover, tissue remodeling, and cellular behavior. Therefore, TIMPs (similar to MMPs) modulate angiogenesis, cell proliferation, and apoptosis. An interruption in the balance between MMPs and TIMPs has been implicated in the pathophysiology and progression of several diseases. This review focuses on the participation of both MMPs (e.g., MMP-2 and MMP-9) and TIMPs (e.g., TIMP-1 and TIMP-3) in physiological processes and on how their abnormal regulation is associated with human diseases. The inclusion of current strategies and mechanisms of MMP inhibition in the development of new therapies targeting MMPs was also considered.

Glycosaminoglycan Modification of Decorin Depends on MMP14 Activity and Regulates Collagen Assembly

Proper processing of collagens COL1 and COL6 is required for normal function of adipose tissue and skeletal muscle. Proteoglycan decorin (DCN) regulates collagen fiber formation. The amino-terminus of DCN is modified with an O-linked glycosaminoglycan (GAG), the function of which has remained unclear. Previously, non-glycanated DCN (ngDCN) was identified as a marker of adipose stromal cells. Here, we identify MMP14 as the metalloprotease that cleaves DCN to generate ngDCN. We demonstrate that mice ubiquitously lacking DCN GAG (ngDCN mice) have reduced matrix rigidity, enlarged adipocytes, fragile skin, as well as skeletal muscle hypotrophy, fibrosis, and dysfunction. Our results indicate that DCN deglycanation results in reduced intracellular DCN—collagen binding and increased production of truncated COL6 chains, leading to aberrant procollagen processing and extracellular localization. This study reveals that the GAG of DCN functions to regulate collagen assembly in adipose tissue and skeletal muscle and uncovers a new mechanism of matrix dysfunction in obesity and aging.

New insights of Krüppel-like transcription factors in adipogenesis and the role of their regulatory neighbors

Obesity is a serious public health problem associated with predisposition to develop metabolic diseases. Over the past decade, several studies in vitro and in vivo have shown that the activity of Krüppel-like factors (KLFs) regulates adipogenesis, adipose tissue function and metabolism. Comprehension of both the origin and development of adipocytes and of adipose tissue could provide new insights into therapeutic strategies to contend against obesity and related metabolic diseases. This review focus on the transcriptional role that KLF family members play during adipocyte differentiation, describes their main interactions and the mechanisms involved in this fine-tuned developmental process. We also summarize new findings of the involvement of several effectors that modulate KLFs expression during adipogenesis, including growth factors, circadian clock proteins, interleukins, nuclear receptors, protein kinases and importantly, microRNAs. Thus, KLFs regulation by these factors and emerging molecules might constitute a potential therapeutic target for anti-obesity intervention.

Effect of Korean Red Ginseng on metabolic syndrome

Metabolic syndrome (MS) refers to a clustering of at least three of the following medical conditions: high blood pressure, abdominal obesity, hyperglycemia, low high-density lipoprotein level, and high serum triglycerides. MS is related to a wide range of diseases which includes obesity, diabetes, insulin resistance, cardiovascular disease, dyslipidemia, or non-alcoholic fatty liver disease. There remains an ongoing need for improved treatment strategies for MS. The most important risk factors are dietary pattern, genetics, old age, lack of exercise, disrupted biology, medication usage, and excessive alcohol consumption, but pathophysiology of MS has not been completely identified. Korean Red Ginseng (KRG) refers to steamed/dried ginseng, traditionally associated with beneficial effects such as anti-inflammation, anti-fatigue, anti-obesity, anti-oxidant, and anti-cancer effects. KRG has been often used in traditional medicine to treat multiple metabolic conditions. This paper summarizes the effects of KRG in MS and related diseases such as obesity, cardiovascular disease, insulin resistance, diabetes, dyslipidemia, or non-alcoholic fatty liver disease based on experimental research and clinical studies.

3D Spheroids Derived from Human Lipedema ASCs Demonstrated Similar Adipogenic Differentiation Potential and ECM Remodeling to Non-Lipedema ASCs In Vitro

The growth and differentiation of adipose tissue-derived stem cells (ASCs) is stimulated and regulated by the adipose tissue (AT) microenvironment. In lipedema, both inflammation and hypoxia influence the expansion and differentiation of ASCs, resulting in hypertrophic adipocytes and deposition of collagen, a primary component of the extracellular matrix (ECM). The goal of this study was to characterize the adipogenic differentiation potential and assess the levels of expression of ECM-remodeling markers in 3D spheroids derived from ASCs isolated from both lipedema and healthy individuals. The data showed an increase in the expression of the adipogenic genes (ADIPOQ, LPL, PPAR-γ and Glut4), a decrease in matrix metalloproteinases (MMP2, 9 and 11), with no significant changes in the expression of ECM markers (collagen and fibronectin), or integrin A5 in 3D differentiated lipedema spheroids as compared to healthy spheroids. In addition, no statistically significant changes in the levels of expression of inflammatory genes were detected in any of the samples. However, immunofluorescence staining showed a decrease in fibronectin and increase in laminin and Collagen VI expression in the 3D differentiated spheroids in both groups. The use of 3D ASC spheroids provide a functional model to study the cellular and molecular characteristics of lipedema AT.

Tissue Inhibitor of Metalloprotease-1 (TIMP-1) Regulates Adipogenesis of Adipose-derived Stem Cells (ASCs) via the Wnt Signaling Pathway in an MMP-independent Manner

Tissue inhibitor of metalloprotease-1 (TIMP-1) is a tissue inhibitor of matrix metalloproteinases (MMPs). It however exerts multiple effects on biological processes, such as cell growth, proliferation, differentiation and apoptosis, in an MMP-independent manner. This study aimed to examine the role of TIMP-1 in adipogenesis of adipose-derived stem cells (ASCs) and the underlying mechanism. We knocked down the TIMP-1 gene in ASCs through lentiviral vectors encoding TIMP-1 small interfering RNA (siRNA), and then found that the knockdown of TIMP-1 in ASCs promoted the adipogenic differentiation of stem cells and inhibited the Wnt/β-catenin signaling pathway in ASCs. We also noted that mutant TIMP-1 without the inhibitory activity on MMPs promoted the activation of Wnt/β-catenin pathway as well as the recombinant wild type TIMP-1 did, which indicated that the effect of TIMP-1 on Wnt/β-catenin pathway was MMP-independent. Our study suggested that TIMP-1 negatively regulated the adipogenesis of ASCs via the Wnt/β-catenin signaling pathway in an MMP-independent manner.

Stromal metalloproteinases: Crucial contributors to the tumor microenvironment

Proteolytic balance is crucial for the maintenance of tissue homeostasis. In cancer, dysregulated proteolysis is involved in unregulated tissue remodeling and inflammation, leading to the promotion of tumor growth, local invasion, and metastasis. Metalloproteinases, which were first identified as collagen cleaving enzymes, have been shown to extensively degrade extracellular matrix proteins or selectively release cell surface-bound cytokines, growth factors, or their receptors, thereby impacting extracellular matrix integrity, immune cell recruitment and tissue turnover. Although tumor cells produce various metalloproteinases, the major source is thought to be stromal cells infiltrating the tumor. Different types of stromal cells express specific sets of metalloproteinases and their inhibitors, which specifically alter the milieu within the tumor. In this review, recent findings and knowledge regarding metalloproteinases derived from stromal cells during the creation of the tumor microenvironment are described and their contribution to the tumor progression and metastasis discussed.

Stabilizing Cellular Barriers: Raising the Shields Against COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its clinical manifestation (COVID-19; coronavirus disease 2019) have caused a worldwide health crisis. Disruption of epithelial and endothelial barriers is a key clinical turning point that differentiates patients who are likely to develop severe COVID-19 outcomes: it marks a significant escalation in respiratory symptoms, loss of viral containment and a progression toward multi-organ dysfunction. These barrier mechanisms are independently compromised by known COVID-19 risk factors, including diabetes, obesity and aging: thus, a synergism between these underlying conditions and SARS-CoV-2 mechanisms may explain why these risk factors correlate with more severe outcomes. This review examines the key cellular mechanisms that SARS-CoV-2 and its underlying risk factors utilize to disrupt barrier function. As an outlook, we propose that glucagon-like peptide 1 (GLP-1) may be a therapeutic intervention that can slow COVID-19 progression and improve clinical outcome following SARS-CoV-2 infection. GLP-1 signaling activates barrier-promoting processes that directly oppose the pro-inflammatory mechanisms commandeered by SARS-CoV-2 and its underlying risk factors.

Estrogen exacerbates mammary involution through neutrophil-dependent and -independent mechanism

There is strong evidence that the pro-inflammatory microenvironment during post-partum mammary involution promotes parity-associated breast cancer. Estrogen exposure during mammary involution drives tumor growth through neutrophils’ activity. However, how estrogen and neutrophils influence mammary involution are unknown. Combined analysis of transcriptomic, protein, and immunohistochemical data in BALB/c mice showed that estrogen promotes involution by exacerbating inflammation, cell death and adipocytes repopulation. Remarkably, 88% of estrogen-regulated genes in mammary tissue were mediated through neutrophils, which were recruited through estrogen-induced CXCR2 signalling in an autocrine fashion. While neutrophils mediate estrogen-induced inflammation and adipocytes repopulation, estrogen-induced mammary cell death was via lysosome-mediated programmed cell death through upregulation of cathepsin B, Tnf and Bid in a neutrophil-independent manner. Notably, these multifaceted effects of estrogen are mostly mediated by ERα and unique to the phase of mammary involution. These findings are important for the development of intervention strategies for parity-associated breast cancer.

Identification and characterization of adipose surface epitopes

Adipose tissue is a central regulator of metabolism and an important pharmacological target to treat the metabolic consequences of obesity, such as insulin resistance and dyslipidemia. Among the various cellular compartments, the adipocyte cell surface is especially appealing as a drug target as it contains various proteins that when activated or inhibited promote adipocyte health, change its endocrine function and eventually maintain or restore whole-body insulin sensitivity. In addition, cell surface proteins are readily accessible by various drug classes. However, targeting individual cell surface proteins in adipocytes has been difficult due to important functions of these proteins outside adipose tissue, raising various safety concerns. Thus, one of the biggest challenges is the lack of adipose selective surface proteins and/or targeting reagents. Here, we discuss several receptor families with an important function in adipogenesis and mature adipocytes to highlight the complexity at the cell surface and illustrate the problems with identifying adipose selective proteins. We then discuss that, while no unique adipocyte surface protein might exist, how splicing, posttranslational modifications as well as protein/protein interactions can create enormous diversity at the cell surface that vastly expands the space of potentially unique epitopes and how these selective epitopes can be identified and targeted.

[Gene-environment interactions between polymorphic loci of MMPs and obesity in essential hypertension in women.]

BACKGROUND

The prevalence of essential hypertension (ЕH) is increasing every year, both in Russia and around the world. Genetic and environmental risk factors are involved in the development of hypertension, and obesity plays an important role. Therefore, the study of gene-ecological interactions in the development of hypertension seems to be relevant.

AIMS

to study the gene-environment interactions between polymorphic loci of MMP and obesity in essential hypertension in women.

MATERIALS AND METHODS

The study was conducted in a case-control design. The sample included 584 subjects: 375 patients with EH and 209 women in the control group. All individuals included in the study were genotyped for eight polymorphic loci of MMPs. The study of the gene-environmental interactions during the formation of hypertension was performed using the GMDR method (Generalized Multifactor Dimensionality Reduction, http://www.ssg.uab.edu/gmdr).

RESULTS

rs11568818 MMР7 and rs11225395 MMР8 polymorphic loci were found to be involved in the development of arterial hypertension in women without obesity (p&lt;0.050). Fifteen three-, four-, and five-factor models of gene-environmental interactions of 8 MMPs with obesity, associated with EH (p=0.01), were found. It is shown that the analyzed SNPs are located in the DNA regions that bind to histones, marking promoters and enhancers, in the region of hypersensitivity to DNAse-1, in the binding sites of regulatory proteins and transcription factors. The loci of MMPs rs17577, rs11568818, rs1320632 and rs11225395 have cis-eQTL-value. They affecting the expression of the genes of MMP7, SNX21, SLC12A5 and RP11-817J15.3.

CONCLUSIONS

SNP rs11568818 MMP7 and rs11225395 MMP8 and gene-environmental interactions of MMPs rs1799750, rs243865, rs3025058, rs11568818, rs1320632, rs11225395, rs17577, rs652438 with obesity are involved in the development of essential hypertension in women.

Critical Role of Matrix Metalloproteinase 14 in Adipose Tissue Remodeling during Obesity

Fibrosis is recognized as the major pathological change in adipose tissue during the development of obesity. However, the detailed mechanisms governing the interactions between the fibrotic components and their modifiers remain largely unclear. Here, we reported that matrix metalloproteinase 14 (MMP14), a key pericellular collagenase, is dramatically upregulated in obese adipose tissue. We generated a doxycycline-inducible adipose tissue-specific MMP14 overexpression model to study its regulatory function. We found that overexpression of MMP14 in the established obese adipose tissue leads to enlarged adipocytes and increased body weights in transgenic mice. Furthermore, the mice exhibited decreased energy expenditure, impaired lipid metabolism, and insulin resistance. Mechanistically, we found that MMP14 digests collagen 6α3 to produce endotrophin, a potent costimulator of fibrosis and inflammation. Unexpectedly, when overexpressing MMP14 in the early-stage obese adipose tissue, the transgenic mice showed a healthier metabolic profile, including ameliorated fibrosis and inflammation, as well as improved lipid and glucose metabolism. This unique metabolic phenotype is likely due to digestion/modification of the dense adipose tissue extracellular matrix by MMP14, thereby releasing the mechanical stress to allow for its healthy expansion. Understanding these dichotomous impacts of MMP14 provides novel insights into strategies to treat obesity-related metabolic disorders.