Cell Communication and Adhesion最新文献

This review article discusses a recent work using engineered cardiac cells to study the function of the intercalated disc putting emphasis on mechanical and electrical coupling.

Cell-cell adhesions serve to mechanically couple cells, allowing for long-range transmission of forces across cells in development, disease, and homeostasis. Recent work has shown that such contacts also play a role in transducing mechanical cues into a wide variety of cellular behaviors important to tissue function. As such, understanding the mechanical regulation of cells through their adhesion molecules has become a point of intense focus. This review will highlight the existing and emerging technologies and models that allow for exploration of cadherin-based adhesions as sites of mechanotransduction.

Cell-cell adhesion is essential for life in multicellular organisms. One of the prominent adhesive structures acting as stabilizing element in tissues is the desmosome. In addition to providing cohesion strength to tissues subjected to high mechanical stress, it has been recently recognized that desmosomes are also essential for tissue morphogenesis and differentiation. The crucial role of the desmosome in cell physiology is mirrored by the large number of diseases occurring when the function of one or more of its constituents is impaired. Hence, major efforts have been made over the last 20 years to understand the mechanisms underlying the pathobiology of intercellular adhesion, with a hope of developing new diagnostic and therapeutic tools; this, in turn, has allowed gaining more insights into the basic science of desmosome structure and function. These concepts will be briefly presented here and developed in detail in the upcoming cell adhesion series "Desmosomes in physiology and disease", launched on the occasion of the 150th anniversary of the discovery of the desmosome in 1864.

In the kidney, the α8 integrin chain (itga8) is expressed in mesenchymal cells and is upregulated in fibrotic disease. We hypothesized that itga8 mediates a profibrotic phenotype of renal cells by promoting extracellular matrix and cytokine expression. Genetic itga8 deficiency caused complex changes in matrix expression patterns in mesangial and smooth-muscle cells, with the only concordant effect in both cell types being a reduction of collagen III expression. Silencing of itga8 with siRNA led to a decline of matrix turnover with repression of matrix metalloproteinases and reduction of matrix production. In contrast, de novo expression of itga8 in tubular epithelial cells resulted in reduced collagen synthesis. Overexpression of itga8 in fibroblasts did not change the expression of matrix molecules or regulators of matrix turnover. Thus, the influence of itga8 on the expression of matrix components was not uniform and celltype dependent. Itga8 seems unlikely to exert overall profibrotic effects in renal cells.

Desmosomes are intercellular junctions that provide tissues with structural stability. These junctions might also act as signaling centers that transmit environmental clues to the cell, thereby affecting cell differentiation, migration, and proliferation. The importance of desmosomes is underscored by devastating skin and heart diseases caused by mutations in desmosomal genes. Recent observations suggest that abnormal desmosomal protein expression might indirectly contribute to skin disorders previously not linked to these proteins. For example, it has been postulated that reduced desmosomal protein expression occurs in patients affected by Ankyloblepharon-ectodermal defects-cleft lip/palate syndrome (AEC), a skin fragility disorder caused by mutations in the transcription factor TP63. Currently, it is not clear how these changes in desmosomal gene expression contribute to AEC. We will discuss new approaches that combine in vitro and in vivo models to elucidate the role of desmosomal gene deregulation in human skin diseases such as AEC.

The classic cardiocutaneous syndromes of Naxos and Carvajal are rare. The myocardial disorder integral to their pathology - arrhythmogenic cardiomyopathy - is arguably not uncommon, with a prevalence of up to 1 in 1,000 despite almost certain under-recognition. Yet the study of cardiocutaneous syndromes has been integral to evolution of the contemporary perspective of arrhythmogenic cardiomyopathy - its clinical course, disease spectrum, genetics, and cellular and molecular mechanisms. Here we discuss how recognition of the association of hair and skin abnormalities with underlying heart disease transformed our conception of a little-understood but important cause of sudden cardiac death.

In this issue, guest editors Kathy Green and Mario Delmar, who are leaders in the fields of epidermal desmosomes and heart intercalated discs respectively, have joined forces to collate a two-part series of reviews focused on junctional proteins and genes that are targets of skin and heart diseases.

Arrhythmogenic cardiomyopathy (AC) is a primary myocardial disorder characterized by a high incidence of ventricular arrhythmias often preceding the onset of ventricular remodeling and dysfunction. Approximately 50% of patients diagnosed with AC have one or more mutations in genes encoding desmosomal proteins, although non-desmosomal genes have also been associated with the disease. Increasing evidence implicates remodeling of intercalated disk proteins reflecting abnormal responses to mechanical load and aberrant cell signaling pathways in the pathogenesis of AC. This review summarizes recent advances in understanding disease mechanisms in AC that have come from studies of human myocardium and experimental models.