Three-dimensional Imaging of the Intracellular Localization of Growth Hormone and Prolactin and Their mRNA Using Nanocrystal (Quantum Dot) and Confocal Laser Scanning Microscopy Techniques

Semiconductor nanocrystals (Quantum dots, Qdots) have recently been used in biological research, because they do not fade on exposure to light, and they enable us to obtain multicolor imaging because of a narrow emission peak that can be excited via a single wavelength of light. There have been no reports of simultaneous localization of mRNA and protein using Qdots. We successfully applied these advantages of Qdot and confocal laser scanning microscopy (CLSM) to three-dimensional images of the intracellular localization of growth hormone and prolactin and to their mRNA. In situ hybridization and immunohistochemistry using Qdots combined with CLSM can optimally illustrate the relationship between protein and mRNA simultaneously in three dimensions. Such an approach enables us to visualize functional images of proteins in relation with mRNA synthesis and localization.

Functional molecular morphology of anterior pituitary cells, from hormone production to intracellular transport and secretion

Combined in situ hybridization (ISH) and immunohistochemistry (IHC) under electron microscopy (EM-ISH & IHC) has sufficient ultrastructural resolution to provide two-dimensional images of subcellular localization of pituitary hormone and its mRNA in a pituitary cell. The advantages of semiconductor nanocrystals (Quantum dots; Qdots) and confocal laser scanning microscopy (CLSM) enable us to obtain three-dimensional images of the subcellular localization of pituitary hormone and its mRNA. Both EM-ISH & IHC and ISH & IHC using Qdots and CLSM are useful for understanding the relationship between protein and mRNA simultaneously in two or three dimensions. CLSM observation of rab3B and SNARE proteins such as SNAP-25 and syntaxin revealed that both rab3B and SNARE system proteins play an important role and work together as the exocytotic machinery in anterior pituitary cells. Another important issue is the intracellular transport and secretion of pituitary hormone. An experimental pituitary cell line, the GH3 cell, in which growth hormone (GH) is linked to enhanced yellow fluorescein protein (EYFP), has been developed. This stable GH3 cell secretes GH linked to EYFP upon being stimulated by Ca(2+) influx or Ca(2+) release from storage. This GH3 cell is useful for real-time visualization of the intracellular transport and secretion of GH. These three methods enable us to visualize consecutively the processes of transcription, translation, transport, and secretion of pituitary hormone.

Molecular morphology of pituitary cells, from conventional immunohistochemistry to fluorescein imaging

In situ hybridization (ISH) at the electron microscopic (EM) level is essential for elucidating the intracellular distribution and role of mRNA in protein synthesis. EM-ISH is considered to be an important tool for clarifying the intracellular localization of mRNA and the exact site of pituitary hormone synthesis on the rough endoplasmic reticulum. A combined ISH and immunohistochemistry (IHC) under EM (EM-ISH&IHC) approach has sufficient ultrastructural resolution, and provides two-dimensional images of the subcellular localization of pituitary hormone and its mRNA in a pituitary cell. The advantages of semiconductor nanocrystals (quantum dots, Qdots) and confocal laser scanning microscopy (CLSM) enable us to obtain three-dimensional images of the subcellular localization of pituitary hormone and its mRNA. Both EM-ISH&IHC and ISH & IHC using Qdots and CLSM are useful for understanding the relationships between protein and mRNA simultaneously in two or three dimensions. CLSM observation of rab3B and SNARE proteins such as SNAP-25 and syntaxin has revealed that both rab3B and SNARE system proteins play important roles and work together as the exocytotic machinery in anterior pituitary cells. Another important issue is the intracellular transport and secretion of pituitary hormone. We have developed an experimental pituitary cell line, GH3 cell, which has growth hormone (GH) linked to enhanced yellow fluorescein protein (EYFP). This stable GH3 cell secretes GH linked to EYFP upon stimulation by Ca²⁺ influx or Ca²⁺ release from storage. This GH3 cell line is useful for the real-time visualization of the intracellular transport and secretion of GH. These three methods from conventional immunohistochemistry and fluorescein imaging allow us to consecutively visualize the process of transcription, translation, transport and secretion of anterior pituitary hormone.

Analyses of the mechanism of intracellular transport and secretion of pituitary hormone, with an insight of the subcellular localization of pituitary hormone and its mRNA

Combined in situ hybridization (ISH) and immunohistochemistry (IHC) under electron microscopy (EM-ISH&IHC) has sufficient ultrastructural resolution and provides two-dimensional images of subcellular localization of pituitary hormone and its mRNA in a pituitary cell. The advantages of semiconductor nanocrystals (Quantum dots, Qdots) and confocal laser scanning microscopy (CLSM) enable us to obtain three-dimensional images of subcellular localization of pituitary hormone and its mRNA. Both EM-ISH&IHC and ISH&IHC using Qdots and CLSM are useful for understanding the relation between protein and mRNA simultaneously in two or three dimensions. Another important issue is the intracellular transport and secretion of pituitary hormone. We have developed an experimental pituitary cell line, the GH3 cell, which has growth hormone (GH) linked to enhanced yellow fluorescein protein (EYFP). This stable GH3 cell secretes GH linked to EYFP upon stimulated by Ca2+ influx or Ca2+ release from storage. This GH3 cell is useful for real-time visualization of the intracellular transport and secretion of GH. These three methods enable us to visualize consecutively the process of transcription, translation, transport, and secretion of pituitary hormone.

Immunohistochemical analysis of neuroendocrine (NE) differentiation in testicular germ cell tumors (GCTs): use of confocal laser scanning microscopy (CLSM) to demonstrate direct NE differentiation from GCTs

Neuroendocrine (NE) differentiation is infrequent in testicular tumors and its histogenesis is not well understood. The present study is aimed at elucidating the pathway of neuroendocrine differentiation in germ cell tumors (GCTs) of the testis. In the analysis of 46 germ cell tumor components from 23 testicular tumors, we focused on GCTs with neuroendocrine differentiation, 7 teratoma, 1 embryonal carcinoma and 1 neuroendocrine carcinoma by immunohistochemical study and confocal laser scanning microscopy (CLSM) analysis. NE marker positive cells were noted in the tumor with collision of teratoma and embryonal carcinoma (E&T tumor), in the immature columnar cells of transitional form of embryonal carcinoma to teratoma (E-T cells) and neuroendocrine carcinoma cells, in addition to the well known mature intestinal mucosa in teratoma. Double staining for a NE marker (CGA) and a germ cell marker (PLAP) demonstrated the localization of both proteins in the same E-T cells confirmed by CLSM. Another finding, indicating the intimate relation between embryonal carcinoma and neuroendcrine differentiation, is that neuroendocrine carcinoma expressed a marker of embryonal carcinoma, CD30. The present results indicated that the NE cells might be differentiated from embryonal carcinoma, a view that has not been proposed before, but that is made in the present study using CLSM.

Dynamics of subcellular organelles, growth hormone, Rab3B, SNAP-25, and syntaxin in rat pituitary cells caused by growth hormone releasing hormone and somatostatin

Rab3B is involved in the exocytosis of synaptic vesicles and secretory granules in the central nervous system and the anterior pituitary cells. The aim of this study was to elucidate both the role of rab3B in GH secretion and the mutual relationship of rab3B and SNARE proteins. Adult male rats were injected intravenously with 10 microg of growth hormone releasing hormone (GHRH) or 10 microg of somatostatin (SRIF). Untreated rats were used as controls, and their pituitary glands were sectioned for histochemical examination. Rab3B is localized on the limiting membrane of the secretory granules and the cytosol. Confocal laser scanning microscopic observation of immunohistochemical double staining of rab3B and GH revealed that immunoreactivity of rab3B increased in GHRH-treated rats and decreased in SRIF-treated rats. Confocal laser scanning microscopic observation of immunohistochemical double staining of SNAP-25, syntaxin, and rab3B revealed the co-localization of rab3B and these SNARE proteins in GHRH-treated rats, and their dissociation in SRIF-treated rats. These results suggest that rab3B plays a principal role in GH secretion in the anterior pituitary cells and that SNAP-25 and syntaxin act as co-workers with rab3B in the functional regulation of GH secretion.