Disintegrin and metalloproteinases (ADAMs and ADAM-TSs), the emerging family of proteases in heart physiology and pathology

The mechanism and therapy of aortic aneurysms

Aortic aneurysm is a chronic aortic disease affected by many factors. Although it is generally asymptomatic, it poses a significant threat to human life due to a high risk of rupture. Because of its strong concealment, it is difficult to diagnose the disease in the early stage. At present, there are no effective drugs for the treatment of aneurysms. Surgical intervention and endovascular treatment are the only therapies. Although current studies have discovered that inflammatory responses as well as the production and activation of various proteases promote aortic aneurysm, the specific mechanisms remain unclear. Researchers are further exploring the pathogenesis of aneurysms to find new targets for diagnosis and treatment. To better understand aortic aneurysm, this review elaborates on the discovery history of aortic aneurysm, main classification and clinical manifestations, related molecular mechanisms, clinical cohort studies and animal models, with the ultimate goal of providing insights into the treatment of this devastating disease. The underlying problem with aneurysm disease is weakening of the aortic wall, leading to progressive dilation. If not treated in time, the aortic aneurysm eventually ruptures. An aortic aneurysm is a local enlargement of an artery caused by a weakening of the aortic wall. The disease is usually asymptomatic but leads to high mortality due to the risk of artery rupture.

A Disintegrin and Metalloproteinase (ADAM) Family-Novel Biomarkers of Selected Gastrointestinal (GI) Malignancies?

The global burden of gastrointestinal (GI) cancers is expected to increase. Therefore, it is vital that novel biomarkers useful for the early diagnosis of these malignancies are established. A growing body of data has linked secretion of proteolytic enzymes, such as metalloproteinases (MMPs), which destroy the extracellular matrix, to pathogenesis of GI tumours. A disintegrin and metalloproteinase (ADAM) proteins belong to the MMP family but have been proven to be unique due to both proteolytic and adhesive properties. Recent investigations have demonstrated that the expression of several ADAMs is upregulated in GI cancer cells. Thus, the objective of this review is to present current findings concerning the role of ADAMs in the pathogenesis of GI cancers, particularly their involvement in the development and progression of colorectal, pancreatic and gastric cancer. Furthermore, the prognostic significance of selected ADAMs in patients with GI tumours is also presented. It has been proven that ADAM8, 9, 10, 12, 15, 17 and 28 might stimulate the proliferation and invasion of GI malignancies and may be associated with unfavourable survival. In conclusion, this review confirms the role of selected ADAMs in the pathogenesis of the most common GI cancers and indicates their promising significance as potential prognostic biomarkers as well as therapeutic targets for GI malignancies. However, due to their non-specific nature, future research on ADAM biology should be performed to elucidate new strategies for the diagnosis of these common and deadly malignancies and treatment of patients with these diseases.

A Disintegrin and Metalloproteinase (ADAM) Family: Their Significance in Malignant Tumors of the Central Nervous System (CNS)

Despite the considerable advances in diagnostic methods in medicine, central nervous system (CNS) tumors, particularly the most common ones-gliomas-remain incurable, with similar incidence rates and mortality. A growing body of literature has revealed that degradation of the extracellular matrix by matrix metalloproteinases (MMPs) might be involved in the pathogenesis of CNS tumors. However, the subfamily of MMPs, known as disintegrin and metalloproteinase (ADAM) proteins are unique due to both adhesive and proteolytic activities. The objective of our review is to present the role of ADAMs in CNS tumors, particularly their involvement in the development of malignant gliomas. Moreover, we focus on the diagnostic and prognostic significance of selected ADAMs in patients with these neoplasms. It has been proven that ADAM12, ADAMTS4 and 5 are implicated in the proliferation and invasion of glioma cells. In addition, ADAM8 and ADAM19 are correlated with the invasive activity of glioma cells and unfavorable survival, while ADAM9, -10 and -17 are associated with tumor grade and histological type of gliomas and can be used as prognostic factors. In conclusion, several ADAMs might serve as potential diagnostic and prognostic biomarkers as well as therapeutic targets for malignant CNS tumors. However, future research on ADAMs biology should be performed to elucidate new strategies for tumor diagnosis and treatment of patients with these malignancies.

Pathogenic mechanisms and the potential of drug therapies for aortic aneurysm

Aortic aneurysm is a permanent focal dilation of the aorta. It is usually an asymptomatic disease but can lead to sudden death due to aortic rupture. Aortic aneurysm-related mortalities are estimated at ∼200,000 deaths per year worldwide. Because no pharmacological treatment has been found to be effective so far, surgical repair remains the only treatment for aortic aneurysm. Aortic aneurysm results from changes in the aortic wall structure due to loss of smooth muscle cells and degradation of the extracellular matrix and can form in different regions of the aorta. Research over the past decade has identified novel contributors to aneurysm formation and progression. The present review provides an overview of cellular and noncellular factors as well as enzymes that process extracellular matrix and regulate cellular functions (e.g., matrix metalloproteinases, granzymes, and cathepsins) in the context of aneurysm pathogenesis. An update of clinical trials focusing on therapeutic strategies to slow abdominal aortic aneurysm growth and efforts underway to develop effective pharmacological treatments is also provided.

Extracellular matrix, regional heterogeneity of the aorta, and aortic aneurysm

Aortic aneurysm is an asymptomatic disease with dire outcomes if undiagnosed. Aortic aneurysm rupture is a significant cause of death worldwide. To date, surgical repair or endovascular repair (EVAR) is the only effective treatment for aortic aneurysm, as no pharmacological treatment has been found effective. Aortic aneurysm, a focal dilation of the aorta, can be formed in the thoracic (TAA) or the abdominal (AAA) region; however, our understanding as to what determines the site of aneurysm formation remains quite limited. The extracellular matrix (ECM) is the noncellular component of the aortic wall, that in addition to providing structural support, regulates bioavailability of an array of growth factors and cytokines, thereby influencing cell function and behavior that ultimately determine physiological or pathological remodeling of the aortic wall. Here, we provide an overview of the ECM proteins that have been reported to be involved in aortic aneurysm formation in humans or animal models, and the experimental models for TAA and AAA and the link to ECM manipulations. We also provide a comparative analysis, where data available, between TAA and AAA, and how aberrant ECM proteolysis versus disrupted synthesis may determine the site of aneurysm formation.

A review of aneurysm formation, swelling in blood vessel, in the aorta, examines distinctions between two forms of the condition and the role of proteins in the extracellular matrix which surrounds cells of the arterial wall. Rupture of aneurysms in the aorta, the body’s main artery, is a major cause of death. Researchers led by Zamaneh Kassiri at the University of Alberta, Edmonton, Canada, emphasize that aneurysms in the thoracic and abdominal regions of the aorta are distinct conditions with crucial differences in their causes. Disrupted production and assembly of the extracellular matrix and its proteins may underlie thoracic aneurysm formation. Factors triggering the degradation of extracellular matrix proteins may be more significant in abdominal aneurysms. Understanding the differing molecular mechanisms involved could help address the current lack of effective drug treatments for these dangerous conditions.

A disintegrin and metalloproteinase 12 prevents heart failure by regulating cardiac hypertrophy and fibrosis

A disintegrin and metalloproteinase (ADAM)12 is considered to promote cardiac dysfunction based on the finding that a small-molecule ADAM12 inhibitor, KB-R7785, ameliorated cardiac function in a transverse aortic constriction (TAC) model by inhibiting the proteolytic activation of heparin-binding-EGF signaling. However, this compound has poor selectivity for ADAM12, and the role of ADAM12 in cardiac dysfunction has not yet been investigated using genetic loss-of-function mice. We revealed that ADAM12 knockout mice showed significantly more advanced cardiac hypertrophy and higher mortality rates than wild-type mice 4 wk after TAC surgery. An ADAM12 deficiency resulted in significantly more expanded cardiac fibrosis accompanied by increased collagen-related gene expression in failing hearts. The results of a genome-wide transcriptional analysis suggested a strongly enhanced focal adhesion- and fibrosis-related signaling pathway in ADAM12 knockout hearts. The loss of ADAM12 increased the abundance of the integrinβ1 subunit and transforming growth factor (TGF)-β receptor types I and III, and this was followed by the phosphorylation of focal adhesion kinase, Akt, mammalian target of rapamycin, ERK, and Smad2/3 in the heart, which resulted in cardiac dysfunction. The present results revealed that the loss of ADAM12 enhanced focal adhesion and canonical TGF-β signaling by regulating the abundance of the integrinβ1 and TGF-β receptors.NEW & NOTEWORTHY In contrast to a long-believed cardio-damaging role of a disintegrin and metalloproteinase (ADAM)12, cardiac hypertrophy was more severe, cardiac function was lower, and mortality was higher in ADAM12 knockout mice than in wild-type mice after transverse aortic constriction surgery. The loss of ADAM12 enhanced focal adhesion- and fibrosis-related signaling pathways in the heart, which may compromise cardiac function. These results provide insights for the development of novel therapeutics that target ADAM12 to treat heart failure.

Disparate Remodeling of the Extracellular Matrix and Proteoglycans in Failing Pediatric Versus Adult Hearts

Background

Dilated cardiomyopathy (DCM) is a common cause of heart failure in adult and pediatric patients, but the underlying mechanism may vary in adults and children, with few studies conducted to date. The objective of the present study was to determine whether differential remodeling of the extracellular matrix contributes to the differences between pediatric and adult DCM hearts.

Methods and Results

Explanted hearts were procured from adult (age, 46–61 years) and pediatric (age, 2–8) patients with DCM‐related heart failure and nonfailing control hearts. Fibrillar and nonfibrillar extracellular matrix (proteoglycans, glycosaminoglycans, glycoprotein), their regulatory enzymes (matrix metalloproteinases, disintegrin and metalloproteinases, and disintegrin and metalloproteinases with a thrombospondin domain), and their inhibitors (tissue inhibitor of metalloproteinases) were assessed. Pediatric DCM hearts exhibited less fibrosis compared with adult DCMs. Total glycosaminoglycans increased similarly in both DCM groups but exhibited a significantly lower affinity for transforming growth factor‐β in adult DCMs versus pediatric DCMs, resulting in increased bioavailability of transforming growth factor‐β1 and a significantly higher activity of the Smad2/3 pathway in adult DCMs. Glycosylated biglycan and versican, and cleaved thrombospondin‐1 increased in both DCMs. Protein expression of disintegrin and metalloproteinases with thrombospondin domains (‐1, ‐2, ‐4, ‐7) and disintegrin and metalloproteinases (‐12, ‐15, ‐17, ‐19) were altered differently in pediatric and adult control and failing hearts. Total matrix metalloproteinase activity increased in both DCMs. Tissue inhibitor of metalloproteinase levels were altered similarly with heart failure in both age groups, and only tissue inhibitor of metalloproteinase 3 decreased in both DCM groups.

Conclusions

Differential remodeling of glycosaminoglycans in pediatric DCMs versus adult DCMs could underlie the enhanced activation of the transforming growth factor‐β pathway, leading to more fibrosis in adult DCM hearts. The distinct remodeling of the fibrillar and nonfibrillar extracellular matrix between pediatric and adult DCM hearts highlights a distinct pathophysiological basis for these cohorts.

Updating the role of matrix metalloproteinases in mineralized tissue and related diseases

Bone development and healing processes involve a complex cascade of biological events requiring well-orchestrated synergism with bone cells, growth factors, and other trophic signaling molecules and cellular structures. Beyond health processes, MMPs play several key roles in the installation of heart and blood vessel related diseases and cancer, ranging from accelerating metastatic cells to ectopic vascular mineralization by smooth muscle cells in complementary manner. The tissue inhibitors of MMPs (TIMPs) have an important role in controlling proteolysis. Paired with the post-transcriptional efficiency of specific miRNAs, they modulate MMP performance. If druggable, these molecules are suggested to be a platform for development of "smart" medications and further clinical trials. Thus, considering the pleiotropic effect of MMPs on mammals, the purpose of this review is to update the role of those multifaceted proteases in mineralized tissues in health, such as bone, and pathophysiological disorders, such as ectopic vascular calcification and cancer.