Gelatinase A (MMP-2) promotes murine adipogenesis

Role of Leptin and Adiponectin in Carcinogenesis

Hormones produced by adipocytes, leptin and adiponectin, are associated with the process of carcinogenesis. Both of these adipokines have well-proven oncologic potential and can affect many aspects of tumorigenesis, from initiation and primary tumor growth to metastatic progression. Involvement in the formation of cancer includes interactions with the tumor microenvironment and its components, such as tumor-associated macrophages, cancer-associated fibroblasts, extracellular matrix and matrix metalloproteinases. Furthermore, these adipokines participate in the epithelial-mesenchymal transition and connect to angiogenesis, which is critical for cancer invasiveness and cancer cell migration. In addition, an enormous amount of evidence has demonstrated that altered concentrations of these adipocyte-derived hormones and the expression of their receptors in tumors are associated with poor prognosis in various types of cancer. Therefore, leptin and adiponectin dysfunction play a prominent role in cancer and impact tumor invasion and metastasis in different ways. This review clearly and comprehensively summarizes the recent findings and presents the role of leptin and adiponectin in cancer initiation, promotion and progression, focusing on associations with the tumor microenvironment and its components as well as roles in the epithelial-mesenchymal transition and angiogenesis.

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.

Quercetin inhibits body weight gain and adipogenesis via matrix metalloproteinases in mice fed a high-fat diet

BACKGROUND/OBJECTIVES

Limited studies reported that quercetin inhibited adipogenesis and neovascularization by inhibiting matrix metalloproteinases (MMPs) activity, but such mechanisms have not been elucidated in animal experiments. In this study, we investigated the inhibitory effects of quercetin on weight gain and adipose tissue growth through the regulation of mRNA expressions of adipogenic transcription factors and MMPs in mice fed a high-fat diet (HFD).

MATERIALS/METHODS

Five-wk-old C57BL/6J mice were fed a normal diet (ND), HFD, HFD containing 0.05% of quercetin (HFQ0.05), or HFD containing 0.15% of quercetin (HFQ0.15) for 16 wks. Glycerol-3-phosphate dehydrogenase (GPDH) activity was measured using a commercial kit. The mRNA expressions of transcription factors related to adipocyte differentiation were determined by real-time polymerase chain reaction (PCR). The mRNA expressions of MMPs and concentrations of MMPs were measured by real-time PCR and enzyme-linked immunosorbent assay kit, respectively.

RESULTS

Quercetin intake reduced body weight gain and epididymal adipose tissue weights (P < 0.05). GPDH activity was higher in the HFD group than in the ND group but lower in the quercetin groups (P < 0.05). The mRNA expressions of CCAAT/enhancer binding protein β (C/EBPβ), C/EBPα, peroxisome proliferator-activated receptor γ, and fatty acid-binding protein 4 were lower in the quercetin groups than in the HFD group (P < 0.05). Similarly, the mRNA expression and concentrations of MMP-2 and MMP-9 were significantly lower in the quercetin groups than in the HFD group (P < 0.05).

CONCLUSION

The study confirms that quercetin suppresses body weight gain and adipogenesis by inhibiting transcription factors related to adipocyte differentiation and MMPs (MMP-2 and MMP-9), in mice fed a HFD.

Anti-Obesity Effect of Rice Bran Extract on High-Fat Diet-Induced Obese Mice

Obesity involving adipose tissue growth and development are associated with angiogenesis and extracellular matrix remodeling. Rice bran has antioxidant and cardioprotective properties, and can act as a food supplement with potential health benefits, such as lowering blood pressure, hepatic steatosis, and inflammation. Therefore, we hypothesized that rice bran extract (RBE) can regulate adipose tissue growth and obesity. Male Institute of Cancer Research mice were fed with a high-fat diet (HFD) for 8 weeks and then supplemented with 220 and 1,100 mg/kg/d RBE while the low-fat diet group (control) were not. In addition to body weight, adipose tissue mass, and vessel density, we evaluated the mRNA expression of angiogenic factors such as matrix metalloproteinases, Mmp-2, Mmp-9, and the vascular endothelial growth factor (Vegf) in visceral and subcutaneous adipose tissues using real-time polymerase chain reaction. Administration of RBE to HFD-induced obese mice reduced the body weight and adipose tissue mass compared with untreated mice. It also decreased blood vessel density in the adipose tissue. Furthermore, RBE downregulated Vegf and Mmp-2 mRNA levels in visceral fat tissue. These results demonstrate that RBE, at high concentrations, significantly reduces adipose tissue mass and prevents obesity development in HFD-induced obese mice, which might be partly mediated via an anti-angiogenic mechanism.

Evaluation of the inflammatory process, collagen production, and MMP-2 and MMP-9 expressions produced by Luffa aegyptiaca Mill using the subcutaneous rat implanted model

The subcutaneous rat implanted model is a preclinical approach used in studies to characterize the histocompatibility of materials that could be used as biomaterials. Biomaterials are obtained synthetically or from the environment, and they can be used to treat or replace any tissues or organs that the body has lost. To execute their roles, the biomaterials must present any level of histocompatibility and a lower level of inflammatory reaction. This work aimed to evaluate some aspects of histocompatibility, such as the inflammatory process, collagen production, and MMP-2 and 9 expression as responses to the Luffa aegyptiaca Mill using the subcutaneous rat implanted model. Luffa fragments were implanted into the dorsal subcutaneous region of twelve male Wistar rats, and the number of eosinophils, mast cells, the production of collagen to form the fibrous capsule, and the expression of MMP-2 and MMP-9 were evaluated on the 15th, 45th, and 90th days. Results showed statistical differences (p < 0.05) in the number of eosinophils and mast cells present inside and outside the fibrous capsule among the days evaluated. The permanent presence of macrophages and giant foreign body cells circumjacent to all implants was also observed. A progressive increase in the production of collagen was also detected, along with a significant reduction on day 90 (p < 0.05). The expression of MMP-9 was detected as being specifically expressed in the giant foreign body cells on all days evaluated, while the expression of MMP-2 was detected in fat cells present around the implants, mainly on day 90. Taken together, these results indicate a general reduction level for the inflammatory process during the days evaluated, which allows us to conclude that Luffa, being a natural product that is simple to obtain, could be a potential candidate to become a biomaterial to be tested in further approaches.

A molecular insight into the lipid changes of pig Longissimus thoracis muscle following dietary supplementation with functional ingredients

In this work, the Longissimus thoracis pig skeletal muscle was used as a model to investigate the impact of two different diets, supplemented with n-3 polyunsaturated fatty acids from extruded linseed (L) and polyphenols from grape skin and oregano extracts (L+P), on the lipidomic profile of meat. A standard diet for growing-finishing pigs (CTRL) was used as a control. Changes in lipids profile were investigated through an untargeted lipidomics and transcriptomics combined investigation. The lipidomics identified 1507 compounds, with 195 compounds fitting with the MS/MS spectra of LipidBlast database. When compared with the CTRL group, the L+P diet significantly increased 15 glycerophospholipids and 8 sphingolipids, while the L diet determined a marked up-accumulation of glycerolipids. According to the correlations outlined between discriminant lipids and genes, the L diet may act preventing adipogenesis and the related inflammation processes, while the L+P diet promoted the expression of genes involved in lipids' biosynthesis and adipogenic extracellular matrix formation and functioning.

Role of Butyrate, a Gut Microbiota Derived Metabolite, in Cardiovascular Diseases: A comprehensive narrative review

Cardiovascular diseases (CVD) are major causes of death worldwide. Recently, new roles for intestinal microbiota in pathology and treatment of CVD have been proposed. Butyrate, a bacterial metabolite, is synthesized in the gut and performs most of its functions in there. However, researchers have discovered that butyrate could enter to portal vein and interact with various organs. Butyrate exhibits a broad range of pharmacological activities, including microbiome modulator, anti-inflammatory, anti-obesity, metabolic pathways regulator, anti-angiogenesis, and antioxidant. In this article we review evidence supporting a potentially therapeutic role for butyrate in CVD and the mechanisms and pathways involved in the cardio-protective effects of butyrate from the gut and circulation to the nervous system. In summary, although butyrate exhibits a wide variety of biological activities in different pathways including energy homeostasis, glucose and lipid metabolism, inflammation, oxidative stress, neural signaling, and epigenetic modulation in experimental settings, it remains unclear whether these findings are clinically relevant and whether the molecular pathways are activated by butyrate in humans.

Whole-Transcriptome Analysis of Preadipocyte and Adipocyte and Construction of Regulatory Networks to Investigate Lipid Metabolism in Sheep

Many local sheep breeds in China have poor meat quality. Increasing intramuscular fat (IMF) content can significantly improve the quality of mutton. However, the molecular mechanisms of intramuscular adipocyte formation and differentiation remain unclear. This study compared differences between preadipocytes and mature adipocytes by whole-transcriptome sequencing and constructed systematically regulatory networks according to the relationship predicted among the differentially expressed RNAs (DERs). Sequencing results showed that in this process, there were 1,196, 754, 100, and 17 differentially expressed messenger RNAs (mRNAs), long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), respectively. Gene Ontology analysis showed that most DERs enriched in Cell Part, Cellular Process, Biological Regulation, and Binding terms. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis found that the DERs primarily focused on Focal adhesion, phosphoinositide 3-kinase (PI3K)-Akt, mitogen-activated protein kinase (MAPK), peroxisome proliferator-activated receptor (PPAR) signaling pathways. Forty (40) DERs were randomly selected from the core regulatory network to verify the accuracy of the sequence data. The results of qPCR showed that the DER expression trend was consistent with sequence data. Four novel promising candidate miRNAs (miR-336, miR-422, miR-578, and miR-722) played crucial roles in adipocyte differentiation, and they also participated in multiple and important regulatory networks. We verified the expression pattern of the miRNAs and related pathways’ members at five time points in the adipocyte differentiation process (0, 2, 4, 6, 8, 10 days) by qPCR, including miR-336/ACSL4/LncRNA-MSTRG71379/circRNA0002331, miR-422/FOXO4/LncRNA-MSTRG54995/circRNA0000520, miR-578/IGF1/LncRNA-MSTRG102235/circRNA0002971, and miR-722/PDK4/LncRNA-MSTRG107440/circ RNA0002909. In this study, our data provided plenty of valuable candidate DERs and regulatory networks for researching the molecular mechanisms of sheep adipocyte differentiation and will assist studies in improving the IMF.

Genomic insights into body size evolution in Carnivora support Peto's paradox

Background

The range of body sizes in Carnivora is unparalleled in any other mammalian order—the heaviest species is 130,000 times heavier than the lightest and the longest species is 50 times longer than the shortest. However, the molecular mechanisms underlying these huge differences in body size have not been explored.

Results

Herein, we performed a comparative genomics analysis of 20 carnivores to explore the evolutionary basis of the order’s great variations in body size. Phylogenetic generalized least squares (PGLS) revealed that 337 genes were significantly related to both head body length and body mass; these genes were defined as body size associated genes (BSAGs). Fourteen positively-related BSAGs were found to be associated with obesity, and three of these were under rapid evolution in the extremely large carnivores, suggesting that these obesity-related BSAGs might have driven the body size expansion in carnivores. Interestingly, 100 BSAGs were statistically significantly enriched in cancer control in carnivores, and 15 of which were found to be under rapid evolution in extremely large carnivores. These results suggested that large carnivores might have evolved an effective mechanism to resist cancer, which could be regarded as molecular evidence to support Peto’s paradox. For small carnivores, we identified 15 rapidly evolving genes and found six genes with fixed amino acid changes that were reported to reduce body size.

Conclusions

This study brings new insights into the molecular mechanisms that drove the diversifying evolution of body size in carnivores, and provides new target genes for exploring the mysteries of body size evolution in mammals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07732-w.

MMP-2 is a novel histone H3 N-terminal protease necessary for myogenic gene activation

BACKGROUND

Selective proteolysis of the histone H3 N-terminal tail (H3NT) is frequently observed during eukaryotic development, generating a cleaved histone H3 (H3cl) product within a small, but significant, portion of the genome. Although increasing evidence supports a regulatory role for H3NT proteolysis in gene activation, the nuclear H3NT proteases and the biological significance of H3NT proteolysis remain largely unknown.

RESULTS

In this study, established cell models of skeletal myogenesis were leveraged to investigate H3NT proteolysis. These cells displayed a rapid and progressive accumulation of a single H3cl product within chromatin during myoblast differentiation. Using conventional approaches, we discovered that the canonical extracellular matrix (ECM) protease, matrix metalloproteinase 2 (MMP-2), is the principal H3NT protease of myoblast differentiation that cleaves H3 between K18-Q19. Gelatin zymography demonstrated progressive increases in nuclear MMP-2 activity, concomitant with H3cl accumulation, during myoblast differentiation. RNAi-mediated depletion of MMP-2 impaired H3NT proteolysis and resulted in defective myogenic gene activation and myoblast differentiation. Supplementation of MMP-2 ECM activity in MMP-2-depleted cells was insufficient to rescue defective H3NT proteolysis and myogenic gene activation.

CONCLUSIONS

This study revealed that MMP-2 is a novel H3NT protease and the principal H3NT protease of myoblast differentiation. The results indicate that myogenic signaling induces MMP-2-dependent H3NT proteolysis at early stages of myoblast differentiation. Importantly, the results support the necessity of nuclear MMP-2 H3NT protease activity, independent of MMP-2 activity in the ECM, for myogenic gene activation and proficient myoblast differentiation.

Regulation of Obesity by Antiangiogenic Herbal Medicines

Obesity is the result of an energy imbalance caused by an increased ratio of caloric intake to energy expenditure. In conjunction with obesity, related metabolic disorders, such as dyslipidemia, atherosclerosis, and type 2 diabetes, have become global health problems. Obesity progression is thought to be associated with angiogenesis and extracellular matrix (ECM) remodeling. Angiogenesis occurs in growing adult adipose tissues, which are similar to neoplastic tissues. Adipose tissue is highly vascularized, and each adipocyte is nourished by an extensive capillary network. Adipocytes produce proangiogenic factors, such as vascular endothelial growth factor A and fibroblast growth factor 2, which promote neovascularization within the adipose tissue. Furthermore, matrix metalloproteinases (MMPs), including MMP-2 and MMP-9, play important roles in adipose tissue development and microvessel maturation by modifying the ECM. Thus, modulation of angiogenesis and MMP activity provides a promising therapeutic approach for controlling human obesity and its related disorders. Over the past decade, there has been a great increase in the use of alternative treatments, such as herbal remedies, for these diseases. This review will focus on the role of angiogenesis in adipose tissue growth and the regulation of obesity by antiangiogenic herbal medicines.

Murine in vitro cellular models to better understand adipogenesis and its potential applications

Adipogenesis has been extensively studied using in vitro models of cellular differentiation, enabling long-term regulation of fat cell metabolism in human adipose tissue (AT) material. Many studies promote the idea that manipulation of this process could potentially reduce the prevalence of obesity and its related diseases. It has now become essential to understand the molecular basis of fat cell development to tackle this pandemic disease, by identifying therapeutic targets and new biomarkers. This review explores murine cell models and their applications for study of the adipogenic differentiation process in vitro. We focus on the benefits and limitations of different cell line models to aid in interpreting data and selecting a good cell line model for successful understanding of adipose biology.

Single-nucleotide polymorphisms for matrix metalloprotease-1 can affect perimysial strength and intramuscular fat content but not growth rate of cattle

Context Single-nucleotide polymorphisms (SNPs) in the gene coding for matrix metalloprotease-1 (MMP-1) are known to affect the level of intramuscular fat found in cattle. As well as a signalling molecule affecting adipogenesis, MMP-1 is a major collagenase involved in the turnover of connective tissue. Aims The aim of the work was to assess whether SNPs in the gene for MMP-1 may affect the mechanical properties of intramuscular connective tissue, and therefore meat texture. Methods Allelic frequencies of three SNPs for MMP-1 were determined in a group of black Aberdeen Angus cattle whose growth characteristics had been traced for 450 days before slaughter. Associations between the alleles of each of the three SNPs and growth rate, killing out percentage, half-carcass weight, intramuscular fat content, cooking loss, strength of perimysium in cooked M. semitendinosus and Warner–Bratzler peak force of cooked M. longissimus dorsi were studied. Key results None of the SNPs studied had any effect on growth curves, and only one SNP (ss77831914) showed differences in half-carcass weight between alleles. Carcass yield and killing out percentage showed a small difference between alleles of ss7783924. No effects were found on the Warner–Bratzler peak force of M. longissimus dorsi cooked to 70°C. Two SNPs (ss77831914 and ss77831924) showed significant differences between alleles in the raw strength of perimysium in M. semitendinosus and the amount of intramuscular fat. Conclusions Commonly occurring SNPs of the major collagenase MMP-1 can affect the strength of intramuscular connective tissue as well as intramuscular fat content. Although these differences in connective tissue strength do not influence Warner–Bratzler measures of toughness at a cooking temperature of 70°C, they may contribute to differences in toughness in low-temperature, long-time cooking. Implications Because none of the SNPs had effects on the growth curves of the cattle studied, selection of animals with the relevant alleles of SNPs ss77831914 ss77831924 could be used to produce more tender meat without affecting carcass yield.

Molecular Mechanism of Stem Cell Differentiation into Adipocytes and Adipocyte Differentiation of Malignant Tumor

Adipogenesis is the process through which preadipocytes differentiate into adipocytes. During this process, the preadipocytes cease to proliferate, begin to accumulate lipid droplets, and develop morphologic and biochemical characteristics of mature adipocytes. Mesenchymal stem cells (MSCs) are a type of adult stem cells known for their high plasticity and capacity to generate mesodermal and nonmesodermal tissues. Many mature cell types can be generated from MSCs, including adipocyte, osteocyte, and chondrocyte. The differentiation of stem cells into multiple mature phenotypes is at the basis for tissue regeneration and repair. Cancer stem cells (CSCs) play a very important role in tumor development and have the potential to differentiate into multiple cell lineages. Accumulating evidence has shown that cancer cells can be induced to differentiate into various benign cells, such as adipocytes, fibrocytes, osteoblast, by a variety of small molecular compounds, which may provide new strategies for cancer treatment. Recent studies have reported that tumor cells undergoing epithelial-to-mesenchymal transition can be induced to differentiate into adipocytes. In this review, molecular mechanisms, signal pathways, and the roles of various biological processes in adipose differentiation are summarized. Understanding the molecular mechanism of adipogenesis and adipose differentiation of cancer cells may contribute to cancer treatments that involve inducing differentiation into benign cells.

Three New Scorpion Chloride Channel Toxins as Potential Anti-Cancer Drugs: Computational Prediction of The Interactions With Hmmp-2 by Docking and Steered Molecular Dynamics Simulations

Scorpion venom is a rich source of toxins which have great potential to develop new therapeutic agents. Scorpion chloride channel toxins (ClTxs), such as Chlorotoxin selectively inhibit human Matrix Methaloproteinase-2 (hMMP-2). The inhibitors of hMMP-2 have potential use in cancer therapy. Three new ClTxs, meuCl14, meuCl15 and meuCl16, derived from the venom transcriptome of Iranian scorpion, M. eupeus (Buthidea family), show high sequence identity (71.4%) with Chlorotoxin. Here, 3-D homology model of new ClTxs were constructed. The models were optimized by Molecular Dynamics simulation based on MDFF (molecular dynamics flexible fitting) method. New ClTxs indicate the presence of CSαβ folding of other scorpion toxins. A docking followed by steered molecular dynamics (SMD) simulations to investigate the interactions of meuCl14, meuCl15, and meuCl16 with hMMP-2 was applied. The current study creates a correlation between the unbinding force and the inhibition activities of meuCl14, meuCl15 and meuCl16 to shed some insights as to which toxin may be used as a drug deliverer. To this aim, SMD simulations using Constant Force Pulling method were carried out. The SMD provided useful details related to the changes of electrostatic, van de Waals (vdW), and hydrogen-bonding (H-bonding) interactions between ligands and receptor during the pathway of unbinding. According to SMD results, the interaction of hMMP-2 with meuCl14 is more stable. In addition, Arginine residue was found to contribute significantly in interaction of ClTxs with hMMP-2. All in all, the present study is a dynamical approach whose results are capable of being implemented in structure-based drug design.

High-Protein Diet Associated with Bocaiuva Supplementation Decreases Body Fat and Improves Glucose Tolerance in Resistance-Trained Rats

High-protein diets (HPDs) are widely used for health and performance. However, the combination of whey protein and natural foods (i.e., fruits) is still unclear. Thus, we evaluated the role of supplemental HPD with Bocaiuva (Acrocomia sp.) in metabolic and body composition parameters of rats submitted to resistance training (RT). Wistar rats (203.3 ± 30 g) were randomly allocated to five groups: normoproteic control (CON, n = 5), sedentary high-protein (SH, n = 5), RT + H (trained high-protein [TH], n = 5), sedentary+Bocaiuva (SH+B, n = 4), and RT+Bocaiuva (TH+B, n = 4) diet groups. After 12 weeks of RT, the maximal strength increased in both trained groups (P < .05). The TH + B group had lower values of adiposity index (AI) (3.8 ± 0.7% vs. 6.8 ± 1.3%) and visceral fat (0.038 ± 0.004 g/g vs. 0.067 ± 0.012 g/g) compared with the SH group, respectively (P < .05). The other groups did not show differences in values of AI (CON, 5.4 ± 1.6%, TH, 5.4 ± 1.3%, and SH+B, 5.5 ± 1.2%). In addition, the fasting glucose of trained groups (TH, 106.0 ± 4.5, and TH+B, 100.4 ± 13.5 dL/mg) was significantly lower when compared with controls (SH, 120.0 ± 14.4, and SH+B, 119 ± 6.4 dL/mg) (P < .05). Bocaiuva combined with an HPD reduced visceral fat and AI in addition to improving glucose tolerance of rats submitted to RT.

MMP-2: is too low as bad as too high in the cardiovascular system?

Matrix metalloproteinase (MMP)-2 cleaves a broad spectrum of substrates, including extracellular matrix components (responsible for normal tissue remodeling) and cytokines (modulators of the inflammatory response to physiological insults such as tissue damage). MMP-2 expression is elevated in many cardiovascular pathologies (e.g., myocardial infarction, hypertensive heart disease) where tissue remodeling and inflammatory responses are perturbed. Thus, it has generally been assumed that blockade of MMP-2 activity will yield therapeutic effects. Here, we provide a counterargument to this dogma based on 1) preclinical studies on Mmp2-null ( Mmp2−/−) mice and 2) clinical studies on patients with inactivating MMP2 gene mutations. Furthermore, we put forward the hypothesis that, when MMP-2 activity falls below baseline, the bioavailability of proinflammatory cytokines normally cleaved and inactivated by MMP-2 increases, leading to the production of cytokines and cardiac secretion of phospholipase A2activity into the circulation, which stimulate systemic inflammation that perturbs lipid metabolism in target organs. Finally, we suggest that insufficient understanding of the consequences of MMP-2 deficiency remains a major factor in the failure of MMP-2 inhibitor-based therapeutic approaches. This paucity of knowledge precludes our ability to effectively intervene in cardiovascular and noncardiovascular pathologies at the level of MMP-2.

Effect of prostaglandin analogs on matrix metalloproteinases and tissue inhibitor of metalloproteinases in eyelid muscle specimens

Purpose

To characterize the effect of prostaglandin analogs (PAs) on tissue specific expression of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) in levator aponeurosis resections (LAR) and conjunctiva-Muller muscle resections (CMMR).

Methods

Specimens from LAR and CMMR of PA users and non-users were analyzed for tissue specific expression of MMP-3, MMP-7, MMP-9 and TIMP-2 using immunohistochemistry. PA use, marginal reflex distances, levator function and palpebral fissure were documented through chart review. The associations between MMP expression, PA exposure time and ocular characteristics were evaluated with a two-factor analysis of variance and multiple correlation analysis.

Results

We observed a tissue specific pattern of expression of MMPs and TIMP-2 in relation to PA exposure between CMMR and LAR specimens. There was increased MMP-7 and TIMP-2 expression in muscle compared to collagen and adipose tissue (P≤0.005), as well as a statistically significant difference in the relationship of MMP-3, MMP-9 and TIMP-2 levels to PA exposure in the two types of muscles (all P≤0.011). Adipose tissue had a PA-dependent reduced expression of MMP-3 (P<0.022), which was seen in both LAR and CMMR. Decreased expression of MMP-3 in collagen correlated with increased dermatochalasis (P<0.045) and steatoblepharon (P<0.018).

Conclusion

PA exposure may affect MMP and TIMP expression in a tissue specific manner, and decreased expression of certain MMPs in collagen correlates to increased clinical measures of prostaglandin associated periorbitopathy (PAP). Further studies with larger samples are needed to ascertain if the changes associated with PAP are due to MMP/TIMP changes or to structural changes.

Mapping novel genetic loci associated with female liver weight variations using Collaborative Cross mice

BACKGROUND

Liver weight is a complex trait, controlled by polygenic factors and differs within populations. Dissecting the genetic architecture underlying these variations will facilitate the search for key role candidate genes involved directly in the hepatomegaly process and indirectly involved in related diseases etiology.

METHODS

Liver weight of 506 mice generated from 39 different Collaborative Cross (CC) lines with both sexes at age 20 weeks old was determined using an electronic balance. Genomic DNA of the CC lines was genotyped with high-density single nucleotide polymorphic markers.

RESULTS

Statistical analysis revealed a significant (P < 0.05) variation of liver weight between the CC lines, with broad sense heritability (H 2) of 0.32 and genetic coefficient of variation (CVG) of 0.28. Subsequently, quantitative trait locus (QTL) mapping was performed, and results showed a significant QTL only for females on chromosome 8 at genomic interval 88.61-93.38 Mb (4.77 Mb). Three suggestive QTL were mapped at chromosomes 4, 12 and 13. The four QTL were designated as LWL1-LWL4 referring to liver weight loci 1-4 on chromosomes 8, 4, 12 and 13, respectively.

CONCLUSION

To our knowledge, this report presents, for the first time, the utilization of the CC for mapping QTL associated with baseline liver weight in mice. Our findings demonstrate that liver weight is a complex trait controlled by multiple genetic factors that differ significantly between sexes.

Extracellular matrix dynamics during mesenchymal stem cells differentiation

Mesenchymal stem cells (MSCs) are stromal cells that display self-renewal and multipotent differentiation capacity. The repertoire of mature cells generated ranges but is not restricted to: fat, bone and cartilage. Their potential importance for both cell therapy and maintenance of in vivo homeostasis is indisputable. Nonetheless, both their in vivo identity and use in cell therapy remain elusive. A drawback generated by this fact is that little is known about the MSC niche and how it impacts differentiation and homeostasis maintenance. Hence, the roles played by the extracellular matrix (ECM) and its main regulators namely: the Matrix Metalloproteinases (MMPs) and their counteracting inhibitors (TIMPs and RECK) upon stem cells differentiation are only now beginning to be unveiled. Here, we will focus on mesenchymal stem cells and review the main mechanisms involved in adipo, chondro and osteogenesis, discussing how the extracellular matrix can impact not only lineage commitment, but, also, their survival and potentiality. This review critically analyzes recent work in the field in an effort towards a better understanding of the roles of Matrix Metalloproteinases and their inhibitors in the above-cited events.

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.

Ciliary Hedgehog Signaling Restricts Injury-Induced Adipogenesis

Injured skeletal muscle regenerates, but with age or in muscular dystrophies, muscle is replaced by fat. Upon injury, muscle-resident fibro/adipogenic progenitors (FAPs) proliferated and gave rise to adipocytes. These FAPs dynamically produced primary cilia, structures that transduce intercellular cues such as Hedgehog (Hh) signals. Genetically removing cilia from FAPs inhibited intramuscular adipogenesis, both after injury and in a mouse model of Duchenne muscular dystrophy. Blocking FAP ciliation also enhanced myofiber regeneration after injury and reduced myofiber size decline in the muscular dystrophy model. Hh signaling through FAP cilia regulated the expression of TIMP3, a secreted metalloproteinase inhibitor, that inhibited MMP14 to block adipogenesis. A pharmacological mimetic of TIMP3 blocked the conversion of FAPs into adipocytes, pointing to a strategy to combat fatty degeneration of skeletal muscle. We conclude that ciliary Hh signaling by FAPs orchestrates the regenerative response to skeletal muscle injury.

Global transcriptome analysis identifies differentially expressed genes related to lipid metabolism in Wagyu and Holstein cattle

Fat deposition of beef cattle varies between breeds. However, the regulation mechanism is still not elucidated completely at molecular level. In the present study, we comparatively analyzed transcriptome of subcutaneous adipose tissue between Wagyu and Holstein cattle with a significant difference in fat deposition to identify key genes associated with fat metabolism and adipogenesis by high-throughput RNA-seq technology. A total of 59,149,852 and 69,947,982 high quality reads were generated, respectively. With further analysis, 662 differentially expressed genes were identified. Gene Ontology and KEGG pathway analysis revealed that many differentially expressed genes were enriched in several biological processes and pathways relevant to adipogenesis and lipid metabolism, in which PPAR and fatty acid metabolism signaling pathways with related genes such as PPARγ, PLIN2 and ELOVL6 et al. play a critical role. Protein-protein interaction network analysis showed EGR1, FOS, SERPINE1, AGT, MMP2 may have great impact on adipocyte differentiation and adipogenesis. Moreover, potential alternative splicing events and single nucleotide polymorphisms (SNPs) were also identified. In summary, we comprehensively analyzed and discussed the transcriptome of subcutaneous adipose tissue of Wagyu and Holstein cattle, which might provide a theoretical basis for better understanding molecular mechanism of fat metabolism and deposition in beef cattle.

Novel Role for Matrix Metalloproteinase 9 in Modulation of Cholesterol Metabolism

Background

The development of atherosclerosis is strongly linked to disorders of cholesterol metabolism. Matrix metalloproteinases (MMPs) are dysregulated in patients and animal models with atherosclerosis. Whether systemic MMP activity influences cholesterol metabolism is unknown.

Methods and Results

We examined MMP‐9–deficient (Mmp9^−/−) mice and found them to have abnormal lipid gene transcriptional responses to dietary cholesterol supplementation. As opposed to Mmp9^+/+ (wild‐type) mice, Mmp9^−/− mice failed to decrease the hepatic expression of sterol regulatory element binding protein 2 pathway genes, which control hepatic cholesterol biosynthesis and uptake. Furthermore, Mmp9^−/− mice failed to increase the expression of genes encoding the rate‐limiting enzymes in biliary cholesterol excretion (eg, Cyp7a and Cyp27a). In contrast, MMP‐9 deficiency did not impair intestinal cholesterol absorption, as shown by the ¹⁴C‐cholesterol and ³H‐sitostanol absorption assay. Similar to our earlier study on Mmp2^−/− mice, we observed that Mmp9^−/− mice had elevated plasma secreted phospholipase A₂ activity. Pharmacological inhibition of systemic circulating secreted phospholipase A₂ activity (with varespladib) partially normalized the hepatic transcriptional responses to dietary cholesterol in Mmp9^−/− mice. Functional studies with mice deficient in other MMPs suggested an important role for the MMP system, as a whole, in modulation of cholesterol metabolism.

Conclusions

Our results show that MMP‐9 modulates cholesterol metabolism, at least in part, through a novel MMP‐9–plasma secreted phospholipase A₂ axis that affects the hepatic transcriptional responses to dietary cholesterol. Furthermore, the data suggest that dysregulation of the MMP system can result in metabolic disorder, which could lead to atherosclerosis and coronary heart disease.

Effects of matrix metalloproteinases on the fate of mesenchymal stem cells

Mesenchymal stem cells (MSCs) have great potential as a source of cells for cell-based therapy because of their ability for self-renewal and differentiation into functional cells. Moreover, matrix metalloproteinases (MMPs) have a critical role in the differentiation of MSCs into different lineages. MSCs also interact with exogenous MMPs at their surface, and regulate the pericellular localization of MMP activities. The fate of MSCs is regulated by specific MMPs associated with a key cell lineage. Recent reports suggest the integration of MMPs in the differentiation, angiogenesis, proliferation, and migration of MSCs. These interactions are not fully understood and warrant further investigation, especially for their application as therapeutic tools to treat different diseases. Therefore, overexpression of a single MMP or tissue-specific inhibitor of metalloproteinase in MSCs may promote transdifferentiation into a specific cell lineage, which can be used for the treatment of some diseases. In this review, we critically discuss the identification of various MMPs and the signaling pathways that affect the differentiation, migration, angiogenesis, and proliferation of MSCs.

Content of Soluble Factors and Characteristics of Stromal Vascular Fraction Cells in Lipoaspirates from Different Subcutaneous Adipose Tissue Depots

BACKGROUND

Although fat grafting has emerged as a major force in plastic, reconstructive, and aesthetic surgery, some questions regarding its reliability and regenerative potential remain unanswered.

OBJECTIVES

The authors examined the influence of three anatomic areas on various lipoaspirate properties to identify the most appropriate harvest site for fat-grafting procedures.

METHODS

Lipoaspirates from 25 healthy patients were harvested from the abdomen, inner thigh, and knee. The authors measured the content of soluble factors in the lipoaspirate followed by the assessment of the yield, adipogenic differentiation, proliferation of stromal vascular fraction (SVF) cells, and the percentage of adipose-derived stem cells (ASC) in the SVF. The results also were correlated with the age and body mass index of the donors.

RESULTS

Lipoaspirates from the abdomen showed significantly higher concentrations of matrix metalloproteinase (MMP)-9 compared with the knee. The content of basic fibroblast growth factor (b-FGF), platelet-derived growth factor (PDGF)-BB, and insulin-like growth factor (IGF)-1 tended to be highest in the abdomen but did not reach statistical significance. Vascular endothelial growth factor (VEGF)-A and bFGF-2 contents both correlated negatively with age in lipoaspirates from at least two different anatomic areas.

CONCLUSIONS

The authors' results indicate that the abdomen may be a slight favorite over the inner thigh and knee because of its richer content of soluble factors. However, because only the difference of MMP-9 content actually reached statistical significance and because no differences in SVF characteristics were observed, a decision primarily based on other criteria appears to be justifiable.

miR-1934, downregulated in obesity, protects against low-grade inflammation in adipocytes

It has been previously demonstrated that miR-1934 was specially regulated by adiponectin, an anti-inflammatory adipokine, in adipose tissue (AT) in vivo. Herein we investigated the role of miR1934 in the regulation of inflammatory response. Compared with chow-diet fed mice, miR1934 expression was down-regulated in epididymal AT of high-fat diet-induced obese mice. miR1934 expression was down-regulated as well in omental AT of obese subjects in comparison with lean subjects. The circulating miR-1934 was also lower in obese subjects and its levels were correlated negatively with body mass index (BMI), waist circumference (WC), low-density lipoprotein cholesterol (LDL-c), insulin resistance and high-sensitivity C-reactive protein (hs-CRP). The down-regulation of miR1934 in obesity was mimicked by TNF-α treatment of 3T3-L1 adipocytes. Moreover, overexpression of miR1934 suppressed the TNF-α-induced gene expression of interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1) in 3T3-L1 adipocytes. De novo formed AT in nude mice transplanted with 3T3-L1 preadipocytes overexpressing miR1934 displayed a reduction in IL-6, TNF-α, IL-1β and an enhancement in IL-10 gene expression when compared with transplant with 3T3-L1 preadipocytes overexpressing miR1934 scrambled control sequence. These results suggest that miR1934 is an important anti-inflammatory factor and may represent a novel mechanism for controlling AT inflammation.

18O-Tracer Metabolomics Reveals Protein Turnover and CDP-Choline Cycle Activity in Differentiating 3T3-L1 Pre-Adipocytes

The differentiation of precursor cells into mature adipocytes (adipogenesis) has been an area of increased focus, spurred by a rise in obesity rates. Though our understanding of adipogenesis and its regulation at the cellular level is growing, many questions remain, especially regarding the regulation of the metabolome. The 3T3-L1 cell line is the most well characterized cellular model of adipogenesis. Using a time course metabolomics approach, we show that the 3T3-L1 preadipocyte metabolome is greatly altered during the first 48 hours of differentiation, where cells go through about two rounds of cell division, a process known as mitotic clonal expansion. Short-chain peptides were among several small molecules that were increased during mitotic clonal expansion. Additional indicators of protein turnover were also increased, including bilirubin, a degradation product of heme-containing proteins, and 3-methylhistidine, a post-translationally modified amino acid that is not reutilized for protein synthesis. To study the origin of the peptides, we treated differentiating preadipocytes with ¹⁸O labeled water and found that ¹⁸O was incorporated into the short chain peptides, confirming them, at least in part, as products of hydrolysis. Inhibitors of the proteasome or matrix metalloproteinases affected the peptide levels during differentiation, but inhibitors of autophagy or peptidases did not. ¹⁸O was also incorporated into several choline metabolites including cytidine 5'-diphosphocholine (CDP-choline), glycerophosphocholine, and several phosphatidylcholine species, indicative of phosphatidylcholine synthesis/degradation and of flux through the CDP-choline cycle, a hallmark of proliferating cells. ¹⁸O-Tracer metabolomics further showed metabolic labeling of glutamate, suggestive of glutaminolysis, also characteristic of proliferating cells. Together, these results highlight the utility of ¹⁸O isotope labeling in combination with metabolomics to uncover changes in cellular metabolism that are not detectable by time-resolved metabolomics.

Matrix metalloproteinase 11 protects from diabesity and promotes metabolic switch

MMP11 overexpression is a bad prognostic factor in various human carcinomas. Interestingly, this proteinase is not expressed in malignant cells themselves but is secreted by adjacent non-malignant mesenchymal/stromal cells, such as cancer associated fibroblasts (CAFs) and adipocytes (CAAs), which favors cancer cell survival and progression. As MMP11 negatively regulates adipogenesis in vitro, we hypothesized that it may play a role in whole body metabolism and energy homeostasis. We used an in vivo gain- (Mmp11-Tg mice) and loss- (Mmp11−/− mice) of-function approach to address the systemic function of MMP11. Strikingly, MMP11 overexpression protects against type 2 diabetes while Mmp11−/− mice exhibit hallmarks of metabolic syndrome. Moreover, Mmp11-Tg mice were protected from diet-induced obesity and display mitochondrial dysfunction, due to oxidative stress, and metabolic switch from oxidative phosphorylation to aerobic glycolysis. This Warburg-like effect observed in adipose tissues might provide a rationale for the deleterious impact of CAA-secreted MMP11, favouring tumor progression. MMP11 overexpression also leads to increased circulating IGF1 levels and the activation of the IGF1/AKT/FOXO1 cascade, an important metabolic signalling pathway. Our data reveal a major role for MMP11 in controlling energy metabolism, and provide new clues for understanding the relationship between metabolism, cancer progression and patient outcome.

The Gustatory Signaling Pathway and Bitter Taste Receptors Affect the Development of Obesity and Adipocyte Metabolism in Mice

Intestinal chemosensory signaling pathways involving the gustatory G-protein, gustducin, and bitter taste receptors (TAS2R) have been implicated in gut hormone release. Alterations in gut hormone profiles may contribute to the success of bariatric surgery. This study investigated the involvement of the gustatory signaling pathway in the development of diet-induced obesity and the therapeutic potential of targeting TAS2Rs to induce body weight loss. α-gustducin-deficient (α-gust^-/-) mice became less obese than wild type (WT) mice when fed a high-fat diet (HFD). White adipose tissue (WAT) mass was lower in α-gust^-/- mice due to increased heat production as a result of increases in brown adipose tissue (BAT) thermogenic activity, involving increased protein expression of uncoupling protein 1. Intra-gastric treatment of obese WT and α-gust^-/- mice with the bitter agonists denatonium benzoate (DB) or quinine (Q) during 4 weeks resulted in an α-gustducin-dependent decrease in body weight gain associated with a decrease in food intake (DB), but not involving major changes in gut peptide release. Both WAT and 3T3-F442A pre-adipocytes express TAS2Rs. Treatment of pre-adipocytes with DB or Q decreased differentiation into mature adipocytes. In conclusion, interfering with the gustatory signaling pathway protects against the development of HFD-induced obesity presumably through promoting BAT activity. Intra-gastric bitter treatment inhibits weight gain, possibly by directly affecting adipocyte metabolism.