The duodenal progenitor population. III. The progenitor cell cycle of principal, goblet and paneth cells

Abstract

The duodenal progenitor population has been investigated with tritium thymidine (H3-T) and autoradiography in male Swiss albino mice to characterize the role that individual cell types (principal, goblet, and Paneth) have in the proliferative activity of the duodenal crypt of Lieberkuhn.Incorporation of H3-T into newly synthesized DNA of all three cell types was observed by one-half after injection of the isotope. Labeled principal and goblet cells were distributed from the first cell of the cryptal mouth to the last cell at the cryptal base. The majority of labeled cells was found in the central region of the crypt. Labeled Paneth cells were restricted to the last four cells at the cryptal base.Analysis of the percentage of labeled metaphase and mitotic figures after H3-T administration showed that the progenitor cycle duration of principal and goblet cells was about 15 hours, while that of Paneth cells was approximately 80 hours. The mean S-phase duration was 7.4, 7.4 and 8.7 hours for principal, goblet, and Paneth cells, respectively, Thus, the GI portion of the cell cycle was considerably longer for Paneth cells, while all phases of the progenitor cycle were of the same duration for principal and goblet cells.It appears from the data that the three cell types of the adult duodenal crypt comprise independent populations capable of self-renewal. Our observations also suggest the existence of causal relationships between the positioning of the proliferative cells types in the duodenal microenvironment and their respective cycle durations.

Optimality in the Development of Intestinal Crypts

“…We then performed single-molecule FISH for Lgr5, combined with fluorescent detection of EdU (Figure 5). Because the duration of S-phase is approximately constant for a broad range of cell types (Cameron and Greulich, 1963; Quastler and Sherman, 1959; Thrasher and Greulich, 1966) and invariant to mouse age (Thrasher and Greulich, 1965), proliferation rate directly correlates with the fraction of cells that are in S-phase (Quastler and Sherman, 1959) (Experimental Procedures).…”

“…Cell cycle period T c was calculated based on the formula introduced by Quastler and Sherman (1959) T c = T S /f , where T S is the S-phase time and f is the fraction of EdU positive cells. T S was estimated at 7.5 hr (Cameron and Greulich, 1963; Quastler and Sherman, 1959; Thrasher and Greulich, 1966). To ensure exclusion of differentiated cells in the calculation of cell cycle period we cohybridized the samples for EdU with single-molecule FISH libraries for Ki67 and included only cells that were positive for Ki67 in the calculations.…”

Paneth Cell Secretion

“…It has been shown that the turnover time for undifferentiated cells in the rat small intestine is 2 days or less [3,19], so that in this time the undifferentiated cells which might have taken up 65Zn would have been lost into the intestinal lumen. However, Paneth cells have a much slower turnover time than goblet or columnar cells [5,12,34], and after 2 days the Paneth cells would be left at the base of the crypts of Lieberkühn. Thus after 2 days or more the source of 05Zn in the small intestine in these experiments would be the Paneth cells.…”

Whole population cell kinetics of mouse duodenal, jejunal, iieal, and colonic epithelia as determined by radioautography and flow cytometry

“…If we assume that the mucous cell population receives no external contribution to its numbers, then using the columnar cell S-phase duration (according to Thrasher and Greulich, 1966, mucous and columnar cells have the same S-phase duration), and the labeling index of mucous cells (Table 4), the turnover time of the mucous cell population could be calculated (this value is not the true mucous cell population turnover time because, as is discussed below, columnar cells contribute heavily to the mucous cell line). These values were included in Table 6.…”