1. Volume 117, Issue 1, Pages 140-148 (July 1999)
Blockade of kit signaling induces transdifferentiation of interstitial cells of Cajal to a smooth muscle phenotype 
Shigeko Torihashi*, Katsuhide Nishi‡, Yoshiko Tokutomi‡, Tetsuo Nishi*, Sean Ward§, Kenton M. Sanders§ 
Gastroenterology 
Volume 117, Issue 1, Pages (July 1999)
DOI: /S (99)
Copyright © 1999 American Gastroenterological Association Terms and Conditions

2. Fig. 1
Whole-mount preparations of ileum and jejunum stained with ACK2 at day 9. (A) Ileum of an animal given 5 injections of ACK2. Nearly all Kit+ cells have disappeared. (B) Jejunum of the same animal revealing Kit+ cells in the region of the myenteric plexus (IC-MY). The network of IC-MY is largely disrupted. (C) Ileum of a control animal. Kit+ multipolar ICC connect together, forming a network. A second population of Kit+ cells (arrows) located at the level of the DMP (IC-DMP) was also observed running parallel to the circular muscle layer (bar = 10 μm).
Gastroenterology  , DOI: ( /S (99) )
Copyright © 1999 American Gastroenterological Association Terms and Conditions

3. Fig. 2
Density of Kit+ cells in the small intestine of control animals (2) and animals given 5 ACK2 treatments (■). The number of Kit+ cells is reduced dramatically by ACK2 treatment throughout the small intestine. There was a gradient in the number of Kit+ cells after ACK2 treatments; more of these cells remained in the oral than in the anal segments.
Gastroenterology  , DOI: ( /S (99) )
Copyright © 1999 American Gastroenterological Association Terms and Conditions

4. Fig. 3
Confocal images of Kit+ cells double-labeled with antifilament proteins. Colocalization of Kit and γ enteric actin immunoreactivities in the jejunum of (A–C) a control animal and (D–F) an animal treated with ACK2. (G–I) Isolated distribution of Kit and desmin immunoreactivities in the control jejunum; (J–L) colocalization of the immunoreactivities in the injected sample, respectively. (M–O) Isolated distribution of Kit and smooth muscle myosin immunoreactivities in the control jejunum; (P–R) colocalization of immunoreactivities in the injected sample, respectively. (A, D, G, J, M, and P) Kit immunoreactivities. (B, E, H, K, N, and Q) Immunoreactivities of filament proteins. (C, F, I, L, O, and R) Kit and filament proteins and their colocalization (yellow). Kit and γ enteric actin are colocalized in both control and experiment. Kit and desmin or smooth muscle myosin are isolated in controls but colocalized in experiment animals. Kit immunoreactivities are shown not only in cell membrane but also in the cytoplasm caused by acetone fixation (bar = 10 μm).
Gastroenterology  , DOI: ( /S (99) )
Copyright © 1999 American Gastroenterological Association Terms and Conditions

5. Fig. 4
Cross sections of the small intestine and the ovary tested for apoptosis. (A) In the small intestine, all nuclei were weakly stained and brightly illuminated nuclei (arrows) show signs of apoptosis in the ileum of a D3 animal given 2 injections of ACK2. Apoptosis was only observed in mucosal cells located in villi; however, nuclei of cells in the muscle layer (M) had no signs of apoptosis. (B) Control section of the ovary indicating apoptosis of follicular epithelial cells (bars = 100 μm).
Gastroenterology  , DOI: ( /S (99) )
Copyright © 1999 American Gastroenterological Association Terms and Conditions

6. Fig. 5
Electron micrographs of the myenteric region of the jejunum at D9. (A) In control animals, IC-MY (IC) had large oval nuclei and electron-dense cytoplasm. These cells were rich in mitochondria (m), and caveolae (arrows) were prominent along their plasma membranes. Well-developed rough endoplasmic reticulum was also observed (rer). Filament structures were rare in IC-MY at this stage in development. IC-MY were easily distinguishable from fibroblasts (F) and neural elements (N). (B) After ACK2 treatment (5 injections), hybrid cells (*) were observed in the same locations normally occupied by IC-MY in the region of the myenteric plexus. These cells had darkly stained cytoplasm and areas rich in microfilaments and intermediate filaments (arrowheads). Caveolae (arrow) were also observed. Cells with this morphology were not observed in tissues of control animals, and they were found only at the level of the myenteric plexus between longitudinal muscle (LM) and circular muscle (CM) layers in ACK2-treated tissues.
Gastroenterology  , DOI: ( /S (99) )
Copyright © 1999 American Gastroenterological Association Terms and Conditions

7. Fig. 6
Immunoelectron micrographs showing localization of Kit in the jejunum of a control animal at D9. (A) IC-MY (IC) were stained by HRP immunohistochemistry, demonstrating expression of Kit in these cells. Reaction product of HRP is deposited in dark bands along the plasma membranes of IC-MY. Darkly stained lysosomes (arrow) within IC-MY were also positive for peroxidase, possibly indicating internalized Kit receptors. (B) A higher magnification of a HRP-positive cell shows a large cluster of mitochondria (m), a characteristic feature of IC-MY. HRP residues were also found around caveolae (arrow).
Gastroenterology  , DOI: ( /S (99) )
Copyright © 1999 American Gastroenterological Association Terms and Conditions

8. Fig. 7
Immunoelectron micrographs showing localization of Kit receptors in a tissue from a D9 animal after 5 injections of ACK2. (A) Kit+ cells (*) contain filaments (arrowheads) running parallel to cell processes. (B) Higher magnification of a process of a Kit-positive cell (*). Electron-dense residues indicating Kit expression are located along the plasma membrane that also contains caveolae (small arrowheads). Bundles of filaments (large arrowheads), composed of microfilaments and intermediate filaments, are prominent. Lysosomes (arrow) were also peroxidase positive.
Gastroenterology  , DOI: ( /S (99) )
Copyright © 1999 American Gastroenterological Association Terms and Conditions

9. Fig. 8
Desmin immunoreactivity in Kit+ cells at D9. (A) Kit+ cells (*) in an animal given 5 injections have intermediate filaments that are labeled with 10-nm gold particles, indicating desmin immunoreactivity. Kit immunoreactivity is demonstrated by electron-dense residues surrounding the cell membranes. Membrane caveolae are also positive for HRP (arrowheads). (B) In control animals, Kit+ cells had many mitochondria (m) and few filament structures. Desmin immunoreactivity was not observed in the cytoplasm of Kit+ cells. However, neighboring smooth muscle cells (SM) were desmin immunopositive, as indicated by 10-nm gold particles decorating intermediate filaments. (C) A micrograph of the area indicated by the thick arrow in B shown at higher magnification. Gold particles, indicating desmin immunoreactivity, are prominent around filaments.
Gastroenterology  , DOI: ( /S (99) )
Copyright © 1999 American Gastroenterological Association Terms and Conditions

10. Fig. 9
Micrographs using conventional and immunoelectron microscopy of cells within the region of the DMP in the jejunum of a D9 animal. (A) IC-DMP (IC) are closely associated with nerve fibers (N) of the DMP as shown by conventional electron microscopy. IC-DMP have electron-dense cytoplasm and many caveolae (arrow). IC-DMP are relatively free of myofilaments compared with surrounding circular muscle fibers (CM). (B) Immunoelectron micrograph from HRP-ACK2–processed tissue showing an undifferentiated cell (*) associated with nerve fibers of the DMP (N) in an animal after 5 injections of ACK2. This type of cell was negative for HRP immunohistochemistry. A neighboring fibroblast (F) has well-developed rough endoplasmic reticulum and is clearly distinguishable from the undifferentiated type of cell. In this animal, neither IC-DMP– nor HRP-positive cells were observed near nerve fibers of the DMP.
Gastroenterology  , DOI: ( /S (99) )
Copyright © 1999 American Gastroenterological Association Terms and Conditions