A simple procedure for morphometric analysis of processes and growth cones of neurons in culture using parameters derived from the contour and convex hull of the object

Kawa, Anna; Stahlhut, Martin; Berezin, Anton; Bock, Elisabeth; Berezin, Vladimir

doi:10.1016/s0165-0270(97)00165-9

Cited by 23 publications

(19 citation statements)

References 16 publications

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“…Phase contrast and fluorescence images were used to determine the overall shape of cells by measuring the cellular perimeter, cellular area, form factor, cellular convex hull, process domain, and process index as described previously for nerve cells (Table 1; Soll et al, 1988;Kawa et al, 1998;Lepekhin et al, 2001). The form factor is defined as (4 ϫ cellular area)/perimeter 2 (Soll et al, 1988).…”

Section: Morphometric Measurements and Statistical Analysismentioning

confidence: 99%

“…The process index is related to the number of cellular processes (e.g., neurites) and is defined as the number of areas contained outside of the cell contour but within the cellular convex hull (Kawa et al, 1998). It has been demonstrated that the process domain correlates with process length and is defined as the difference between the areas of the cellular convex hull and the cellular area (Kawa et al, 1998). All data were subsequently analyzed by Microsoft Excel, and a Student's t test (unpaired, two-tailed) was used to determine any significant differences (p Ͻ 0.005) between the parameters measured in the peripherin siRNA-transfected and control or mock-transfected cells.…”

Section: Morphometric Measurements and Statistical Analysismentioning

confidence: 99%

“…To more accurately assess the effects of peripherin-siRNA on PC12 cell morphology, the cellular perimeter, mean cell area, form factor, process domain, and process index were determined (Table 1, a and b; see MATERIALS AND METHODS). In particular, the form factor, process index, and process domain values reflect the roundness of cells, number of processes, and process length, respectively (Kawa et al, 1998;Soll et al, 1988). The resulting data revealed that the overall shape of peripherin-silenced cells and control cells was different as reflected by their increased form factor values and decreased process index and process domain values (Table 1).…”

Section: Peripherin Sirna Decreases the Level Of Peripherin Expressionmentioning

confidence: 99%

“…Thus, perfectly round cells have a form factor of 1, whereas stellate cells have lower form factor values (Soll et al, 1988). The cellular convex hull delineates the boundaries of a cell by connecting the tips of processes (for an example, see Table 1, a and b; Kawa et al, 1998). After establishing the convex hull, the process index and process domains were determined (for an example, see Table 1, a and b).…”

mentioning

confidence: 99%

“…After establishing the convex hull, the process index and process domains were determined (for an example, see Table 1, a and b). The process index is related to the number of cellular processes (e.g., neurites) and is defined as the number of areas contained outside of the cell contour but within the cellular convex hull (Kawa et al, 1998). It has been demonstrated that the process domain correlates with process length and is defined as the difference between the areas of the cellular convex hull and the cellular area (Kawa et al, 1998).…”

mentioning

confidence: 99%

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A Role for Intermediate Filaments in Determining and Maintaining the Shape of Nerve Cells

Helfand

Mendez

Pugh

et al. 2003

MBoC

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To date, the functions of most neural intermediate filament (IF) proteins have remained elusive. Peripherin is a type III intermediate filament (IF)protein that is expressed in developing and in differentiated neurons of the peripheral and enteric nervous systems. It is also the major IF protein expressed in PC12 cells, a widely used model for studies of peripheral neurons. Dramatic increases in peripherin expression have been shown to coincide with the initiation and outgrowth of axons during development and regeneration, suggesting that peripherin plays an important role in axon formation. Recently, small interfering RNAs (siRNA) have provided efficient ways to deplete specific proteins within mammalian cells. In this study, it has been found that peripherin-siRNA depletes peripherin and inhibits the initiation, extension, and maintenance of neurites in PC12 cells. Furthermore, the results of these experiments demonstrate that peripherin IF are critical determinants of the overall shape and architecture of neurons. INTRODUCTIONThe cytoskeleton of vertebrate cells consists of three major types of protein networks: intermediate filaments (IF), microfilaments (MF), and microtubules (MT). Intermediate filaments are the most diverse of the three because they are encoded by Ͼ65 genes, making the IF superfamily one of the 100 largest in the human genome (Hesse et al., 2001). These genes are developmentally regulated, resulting in the cell type-specific expression of IF. This is clearly evident in the nervous system, where at least seven different IF proteins are expressed, ranging from the complex neurofilament (NF) heteropolymers composed of the type IV triplet proteins NF-L, NF-M, and NF-H, to the simpler homopolymers of the type III IF protein peripherin (Leung et al., 1998). Peripherin forms the major IF system of peripheral and enteric neurons, and it is abundantly expressed in PC12 cells, a widely used model for studies of peripheral neurons (Parysek and Goldman, 1987;Leonard et al., 1988; Portier et al., 1983a,b).One of the hallmarks of mature or terminally differentiated neurons is their remarkable shape, highlighted by extremely long cytoplasmic processes such as axons. The initiation, extension, and maintenance of axons involve the coordinated interactions of different cytoskeletal proteins (Mueller, 1999;Dickson, 2002). To date, only MT and MF have been considered essential for growth cone activity and axon outgrowth (Letourneau, 1996). In contrast, the contribution of neural IF to these processes has not been defined.The expression patterns of neural IF are highly correlated with different phases of axonal development. Type III IF, such as peripherin and vimentin, are present throughout early stages of outgrowth, and later type IV NF triplet proteins are expressed as axons reach maturity (Cochard and Paulin, 1984;Troy et al., 1990a). In mature neurons, NF appear to be major determinants of axon caliber, and thus conduction velocity (Lasek et al., 1983;Hoffman et al., 1987). However, little is known about ...

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