Both connective tissue mast cells and mast cells grown in vitro are derived from multipotential hematopoietic stem cells, but these two mast cell populations exhibit many differences in morphology, biochemistry, and function. We investigated whether the phenotype of cultured mast cells or their progeny was altered when the cells were transferred into different locations in vivo. Cultured mast cells were immature by ultrastructure, and stained with alcian blue but with neither safranin or berberine sulfate, a fluorescent dye that binds to the heparin of connective tissue mast cell granules. By contrast, mast cells recovered from the peritoneal cavity of congenitally mast cell-deficient (WB X C57BL/6)F1-W/Wv (WBB6F1-W/Wv) mice 10 wk after intraperitoneal injection of cultured WBB6F1-+/+ or C57BL/6-bgJ/bgJ mast cells stained with both safranin and berberine sulfate. Staining with berberine sulfate was prevented by treatment of the cells with heparinase but not chondroitinase ABC, suggesting that the adoptively transferred mast cell population had acquired the ability to synthesize and store heparin. Furthermore, the recovered mast cells were indistinguishable by ultrastructure from the normal mature peritoneal mast cells of WBB6F1-+/+ mice, and contained substantially more histamine than mast cells studied directly from culture. Intravenous injection of cultured mast cells resulted in the development of safranin-and berberine sulfate-positive mast cells in the peritoneal cavity, spleen, skin, and glandular stomach muscularis propria. Mast cells also developed on the glandular stomach mucosa, but these cells stained with alcian blue rather than safranin, and did not stain with berberine sulfate. This result suggests that cultured mast cells can give rise to mast cells of either the connective tissue type or mucosal phenotype, depending on anatomical location. Furthermore, transplantation of cultured mast cells into WBB6F1-W/Wv mice had no measurable effect on the anemia of the recipient mice, suggesting a possible strategy for repairing the mast cell deficiency of WBB6F1-W/Wv mice without affecting other bone marrow-derived populations such as erythrocytes. Intravenous injection of representative connective tissue type mast cells (30-50% pure peritoneal mast cells derived from WBB6F1-+/+ mice) gave results similar to those obtained with cultured mast cells: mast cells developing in the peritoneal cavity, skin, spleen, and glandular stomach muscularis propria of WBB6F1-W/Wv recipients stained with safranin and berberine sulfate, whereas mast cells developing in the mucosa of the glandular stomach stained only with alcian blue.(ABSTRACT TRUNCATED AT 400 WORDS)

The ability of mouse IL-3-dependent, bone marrow culture-derived mast cells (BMMC) to generate serosal mast cells (SMC) in vivo after adoptive transfer to mast cell-deficient mice has been defined by chemical and immunochemical criteria. BMMC differentiated and grown from WBB6F1-+/+ mouse progenitor cells in medium containing PWM/splenocyte-conditioned medium synthesized a approximately 350,000 Mr protease-resistant proteoglycan bearing approximately 55,000 Mr glycosaminoglycans, as defined by gel filtration of each. Approximately 85% of the glycosaminoglycans bound to the cell-associated BMMC proteoglycans were chondroitin sulfates based upon their susceptibility to chondroitinase ABC digestion; HPLC of the chondroitinase ABC-generated unsaturated disaccharides revealed these glycosaminoglycans to be chondroitin sulfate E. As determined by heparinase and nitrous acid degradations, approximately 10% of the glycosaminoglycans bound to BMMC proteoglycans were heparin. In contrast, mast cells recovered from the peritoneal cavity of congenitally mast cell-deficient WBB6F1-W/Wv mice 15 wk after intraperitoneal injection of BMMC synthesized approximately 650,000 Mr protease-resistant proteoglycans that contained approximately 80% heparin glycosaminoglycans of approximately 105,000 Mr. Thus, after adoptive transfer, the SMC of the previously mast cell-deficient mice were like those recovered from the normal WBB6F1-+/+ mice that were shown to synthesize approximately 600,000 Mr proteoglycans that contained approximately 80% heparin glycosaminoglycans of approximately 115,000 Mr. As assessed by indirect immunofluorescence staining and flow cytometry using the B1.1 rat mAb (an antibody that recognizes an epitope located on the neutral glycosphingolipid globopentaosylceramide), approximately 5% of BMMC bound the antibody detectably, whereas approximately 72% of the SMC that were harvested from mast cell-deficient mice 15 wk after adoptive transfer of BMMC were B1.1-positive; approximately 82% of SMC from WBB6F1-+/+ mice bound the antibody. These biochemical and immunochemical data are consistent with the results of previous adoptive transfer studies that characterized mast cells primarily on the basis of morphologic and histochemical criteria. Thus, IL-3-dependent BMMC developed in vitro, cells that resemble mucosal mast cells, can give rise in vivo to SMC that express phenotypic characteristics of connective tissue mast cells.

In spite of the apparent depletion of mast cells in tissues of mutant mice of W/Wv genotype, cells with many features of mast cells do develop when bone marrow cells of W/Wv mice are cultured in the presence of pokeweed mitogen-stimulated spleen cell-conditioned medium (PWM-SCM). In order to resolve this discrepancy and facilitate the analysis of the W mutation, we attempted to establish an in vitro system in which the in vivo defect of W/Wv mice can be reproduced. Cultured mast cells (CMC) were developed from bone marrow cells of either W/Wv or congenic +/+ mice, and then co-cultured with NIH/3T3 mouse fibroblasts in media supplemented only with fetal calf serum (i.e., in the absence of PWM-SCM). Under this condition, CMC from +/+ mice continued to divide and were maintained for more than 4 weeks. The supportive effect of NIH/3T3 cells required close-range interactions with CMC and was not due to synthesis of the known mast cell growth factors, interleukins 3 and 4. By contrast, CMC from W/Wv mice were not maintained, and the number of mast cells remaining after 4 weeks of co-culture was only 1% of the normal +/+ counterparts. Thus, the humoral factor-independent and cell contact-dependent system presented here revealed the intrinsic defects in growth and differentiation of CMC derived from W/Wv mice and might be useful for biochemical and molecular analysis of the gene product(s) encoded at the W locus.

Connective tissue mast cells (CTMC) and mucosal mast cells (MMC) are apparently different, but the ontologic relationship between these two types of mast cells was unclear. We investigated the relationship by combining in vivo and in vitro techniques. Although bone marrow-derived mast cells developed in suspension culture resemble MMC, they acquired histochemical, electron microscopical, biochemical and immunological characteristics of CTMC after the transfer into the peritoneal cavity of genetically mast cell-deficient WBB6F₁-W/W^v mice. On the other hand, when single peritoneal mast cells (typical CTMC) of WBB6F₁-+/+ mice were injected into the stomach wall of WBB6F₁-W/W^v mice, CTMC appeared in the muscularis propria and MMC in the mucosa. These results suggest that CTMC and MMC may interchange and that their phenotypes are determined by the anatomical microenvironment in which the final differentiation occurs.

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Aim: To assess whether FOXL2 p.C134W mutation may play a role in the development of human ovarian tumors in the Japanese, we investigated the FOXL2 codon 134 mutation and protein expression of inhibin-α, bone morphogenetic protein 2 (BMP2) and follistatin (FST) in Japanese patients with granulosa cell tumor (GCT) of the ovary and other ovarian tumors. Methods: We analyzed 114 tumor tissues from ovarian tumors, including 44 adult-type and two juvenile-type GCT of the ovary and 68 ovarian tumors by DNA sequencing. Immunohistochemistry was also performed in the adult and juvenile GCT tissues by immunostaining inhibin-α, BMP2 and FST. Results: We found the FOXL2 p.C134W mutation in 27 out of 44 (61.4%) adult-type GCT of the ovary, but none in other ovarian tumors. Histologically, all of the adult-type GCT sections were positive for inhibin-α, and the expression of BMP2 and FST was detected in 14 of 44 (31.8%) and zero of 47 (0%), respectively. No significant differences regarding the diagnosed age, preoperative serum carbohydrate antigen 125 levels, or BMP2 immunopositivity between the FOXL2 p.C134W mutation-positive and mutation-negative were found in the adult-type GCT patients. Conclusion: Our findings suggest that FOXL2 p.C134W mutation-positive adult-type GCT of the ovary may not be common in the Japanese as compared to the previous data.

Mice of mutant genotypes were used to investigate the differentiation process of connective tissue mast cells. Mast cell precursors, which are a progeny of the multipotential hematopoietic stem cell, leave the bone marrow, migrate in the bloodstream and enter into connective tissues where they proliferate and differentiate into mast cells. A portion of morphologically identifiable mast cells may function as committed and localized mast cell precursors. When local production of mast cells is demanded, the mast cells with proliferative potentiality respond first. Further demand is met by invasion and differentiation of marrow-derived precursors.

Mouse peritoneal mast cells (PMC) express a connective tissue-type mast cell (CTMC) phenotype, including reactivity with the heparin-binding fluorescent dye berberine sulfate and incorporation of [35S] sulfate predominantly into heparin proteoglycans. When PMC purified to greater than 99% purity were cultured in methylcellulose with IL-3 and IL-4, approximately 25% of the PMC formed colonies, all of which contained both berberine sulfate-positive and berberine sulfate-negative mast cells. When these mast cells were transferred to suspension culture, they generated populations that were 100% berberine sulfate-negative, a characteristic similar to that of mucosal mast cells (MMC), and that synthesized predominantly chondroitin sulfate [35S] proteoglycans. When “MMC-like” cultured mast cells derived from WBB6F1-+/+ PMC were injected into the peritoneal cavities of mast cell-deficient WBB6F1- W/Wv mice, the adoptively transferred mast cell population became 100% berberine sulfate-positive. In methylcellulose culture, these “second generation PMC” formed clonal colonies containing both berberine sulfate-positive and berberine sulfate-negative cells, but exhibited significantly less proliferative ability than did normal +/+ PMC. Thus, clonal mast cell populations initially derived from single PMC exhibited multiple and bidirectional alterations between CTMC-like and MMC-like phenotypes. However, this process was associated with a progressive diminution of the mast cells' proliferative ability.