Archives of histology and cytology最新文献

Three mammalian GGAs (Golgi-localized, gamma-ear-containing, ARF-binding proteins), GGA1, 2, and 3 have been implicated in the sorting of mannose 6-phosphate receptor (MPR). To investigate the distinct roles of GGA2 in lysosomal enzyme transport, we established two stable cell lines that had a reduced expression of GGA2 by RNA interference. The expression levels of GGA2 were approximately 5% of the control levels, whereas those of non-targeted GGA1 and GGA3 were not apparently reduced. The depletion of GGA2 did not cause changes in the overall distribution of GGA1, GGA3, cation-dependent MPR, or cation-independent MPR. However, the cell lines showed increased secretion of a lysosomal enzyme, cathepsin D. In addition, a moderate expression of the dominant negative VHS-GAT domain of GGA2 had no effect on the trans-Golgi network (TGN) signal of three GGAs, nor was the GGA2 signal affected by the expression of VHS-GAT domain of GGA1 or 3. These results suggest that GGA2 is recruited to the TGN independently of the other GGAs and is required for the efficient sorting of lysosomal enzymes.

We studied distribution patterns of type IV collagen alpha chains in the subepithelial basement membrane (SBM) of the human gastrointestinal tract - the esophagus through the anal canal - by immunofluorescent microscopy using alpha(IV) chain-specific monoclonal antibodies. The alpha1(IV), alpha2(IV), alpha5(IV), and alpha6(IV) chains were found in the SBM throughout the tract, indicating the localization of [alpha1(IV)](2)alpha2(IV) and [alpha5(IV)](2)alpha6(IV) heterotrimeric molecules. The [alpha1(IV)](2)alpha2(IV) molecule was continuously stained, while the [alpha5(IV)](2)alpha6(IV) molecule was weakly stained in gastric glands and small intestinal crypts. In addition, the SBM at the luminal surface epithelium of the stomach and large intestine contained small amounts of alpha3(IV) and alpha4(IV) chains which combined to form the alpha3(IV)alpha4(IV)alpha5(IV) heterotrimeric molecule with alpha5(IV) chain. The SBM beneath the villous epithelium of the small intestine was also demonstrated to have an alpha3(IV) chain and alpha4(IV) chain. Considering the specific locations of the type IV collagen trimers throughout the gastrointestinal SBM, the supramolecular network containing the alpha3(IV)alpha4(IV)alpha5(IV) molecule appears to function as a selective permeability barrier and /or as a protection against chemical stress from the luminal digestive enzymes.

Carbocyanine fluorescent dye, DiI, is an excellent anterograde/retrograde neural tracer, but its efficacy for the anterograde labeling of neural circuits in the adult brain tends to decrease with ages. The present study shows that an injection of DiI into the motor cortex of the young adult jimpy mutant mice (Plp1(jp)/+) resulted in successful anterograde labeling of corticospinal tract fibers. Furthermore, an injection of Fast Blue into the lumbar spinal cord of the mutant mice resulted in retrograde labeling of layer 5 corticospinal tract neurons within the motor cortex. Since no abnormality except for myelin deficiency is known in the long descending and ascending tracts of jimpy mutant mouse, this mutant is suitable for neural tracing studies of long axonal trajectories with the use of carbocyanine dye, DiI, although these males die between 20 and 40 days of age.

Cell proliferation in the pineal organ of the immature rainbow trout Oncorhynchus mykiss was investigated by immunocytochemical demonstration of the proliferating cell nuclear antigen (PCNA) together with photoreceptor-specific opsin. Numerous PCNA-immunoreactive cells were found throughout the pineal end-vesicle and stalk. Two types of PCNA-immuno-reactive cells were distinguished: intensely stained, large ovoid and round cells, and mildly stained, slender fusiform cells. The ovoid type of the former cell was found often in the apical region and the round type in the basal region of the epithelium, while the latter fusiform cells were scattered through the apical and middle regions. Occasionally, close approaches were found between the opsin-immunoreactive photoreceptor outer segments and the PCNA-immunoreactive cells, which expressed mildly stained, nuclear and cytoplasmic signals. In addition, overlaps of the opsin-immunoreactive outer segments with the BrdU-labelled cells were occasionally found within the pineal epithelium. These findings suggest that the proliferation and neurogenesis of the pineal photoreceptor cells might persist also in the adult rainbow trout, thus maintaining highly sensitive, photo-signal transduction mechanisms for melatonin synthesis.

The present study aims to identify alpha chains of type IV collagen in the basement membrane of the mouse ovarian follicle and examine their changes during follicular development using immunofluorescence microscopy with specific monoclonal antibodies. The basement membrane of the serous mesothelium enveloping the ovary contained all alpha chains of type IV collagen, alpha1(IV) through alpha6(IV) chains. Primordial follicles showed a distinct immunoreactivity against all six alpha chains in their basement membranes. Immunolabeling for alpha3(IV) and alpha4(IV) chains was almost eliminated in the primary follicles. In basement membranes of secondary and Graafian follicles, the immunofluorescent reaction of alpha3(IV) and alpha4(IV) chains disappeared in Graafian follicles, a partial reduction in fluorescent immunostaining intensity to alpha5(IV) and alpha6(IV) chains was observed; only alpha1(IV) and alpha2(IV) chains were not degraded throughout follicular development. On atretic follicles, in addition to alpha1(IV) and alpha2(IV) chains, alpha3(IV), alpha4(IV), alpha5(IV) and alpha6(IV) chains frequently persisted. A basement membrane-like matrix within the follicular granulosa cell layer, such as the focimatrix (focal intraepithelial matrix) and/or Call-Exner body, was also recognized in mouse secondary and Graafian follicles and contained alpha1(IV), alpha2(IV), alpha5(IV) and alpha6(IV) chains but not alpha3(IV) and alpha4(IV) chains. We expect that the decrease in alpha(IV) chains prompts follicular development and is a prerequisite condition for follicular maturation.

The present study was performed to examine the distribution and distinct morphology of the serotonin-containing enterochromaffin (EC) cells in the rat distal colon by immunohistochemical and electron microscopic methods. Serotonin-immunohistochemistry revealed that most of the serotonin-immunoreactive EC cells possessed extended cytoplasmic processes. In particular, the immunoreactive EC cells with long processes located along the body of the crypt were characterized by their bipolar processes comprising one with the terminal swellings extending vertically down to the basal crypt and the other running up along the luminal side - in many cases, with the apical ends reaching the glandular lumen. Moreover, a few EC cells had long processes which resembled neuronal processes with varicosities. Electron microscopic observations revealed rod-like, tortuous, oval, or round small pleomorphic granules in the long processbearing EC cells. The cell bodies and processes directly faced the crypt epithelial cells - including the enterocytes and goblet cells on one side and the basement membrane on the opposite side. The accumulation of the granules sometimes appeared within the cytoplasm on the side of the epithelial cells. These findings suggest that serotonin is released from the long processes of the EC cells and directly acts in a paracrine fashion on the crypt epithelial cells to secrete electrolytes and fluids into the colonic lumen. The long cytoplasmic processes of the EC cells may be a major contributor to the serotonininduced secretory events in the rat distal colon.

The present study demonstrated for the first time the localizations and patterns of expression of key enzymes for steroidogenesis, cytochrome P450 side-chain-cleavage (P450scc), and P450 aromatase in the taste buds of rat circumvallate papillae, using immunoblot analyses and immunohistochemistry. Immunoblot analyses showed that proteins with a molecular weight close to that of rat adrenal cytochrome P450scc and a molecular weight close to that of rat ovary cytochrome P450 aromatase were present in the rat circumvallate papillae. In immunohistochemistry, antibodies against cytochrome P450scc and P450 aromatase yielded the labelings of a subset of taste bud cells. In the double immunolabeling of P450scc and alpha-gustducin or phospholipase C beta2(PLCbeta2), which were considered as markers of a majority of type II cells, P450scc was co-expressed in a subset of alpha-gustducin or PLCbeta2, but did not co-express neural adhesion molecule (NCAM), a marker of major type III cells. Further double immunolabeled studies showed that P450 aromatase was co-expressed in a subset of alpha-gustducin or PLCbeta2, but did not co-express PGP9.5, a marker of a majority of type III cells. The selective localization of cytochrome P450scc and P450 aromatase strongly suggests that estrogen biosynthesis from cholesterol might occur in a subset of type II cells of the rat taste buds. Although the full significance of estrogen in the taste bud function is not yet understand, estrogen appears to be an important regulator of taste transduction, as is the case with ATP (Finger et al., 2005), which further supports the centrality of taste cells in the life of taste buds.

Distributions of type IV collagen alpha chains in the basement membrane (BM) of human skin and its appendages were analyzed by immunofluorescent microscopy using chain-specific monoclonal antibodies. The basement membrane beneath the epidermis contained [alpha1(IV)](2)alpha2(IV) and [alpha5(IV)](2)alpha6(IV) but no alpha3(IV)alpha4(IV)alpha5(IV); this held true for at the eccrine sweat glands and glandular ducts, sebaceous glands, hair follicles, and arrector muscles of hair. The secretary portion of the eccrine sweat glands was rich in [alpha1(IV)](2) alpha2(IV) and had less [alpha5(IV)](2)alpha6(IV), while [alpha5(IV)](2) alpha6(IV) was abundant in the ductal portion. In the subepidermal zone, alpha5(IV)/alpha6(IV) chain negative spots (1.9-15.0 microm) were frequently observed. Triple staining samples (Mel.2, alpha2(IV) and alpha5(IV) chains) showed that about 50% of epidermal melanocytes colocalized with such spots. Results suggest that these alpha5(IV)/alpha6(IV) chain negative spots of the subepidermal basement membrane have a particular relationship with melanocytes and are sites for certain interactions between the two.

We investigated cyclooxygenase-2 (Cox-2) immunoreactive cells in the hippocampus and dentate gyrus of Sprague-Dawley rats at 4 h after the induction of normothermic and hypothermic ischemia and reperfusion. Under the normothermic condition, Cox-2 immunoreactive cells showed more intense staining and clearer proximal dendrite configurations as compared with the control animals, whereas the numbers of immunoreactive cells in the hippocampus and dentate gyrus were not remarkably increased. In contrast to the normothermic condition, long-term (pre- and intra-ischemic) and short-term (exclusively intra-ischemic) hypothermic conditions caused a drastic increase in immunoreactive cells in the dentate gyrus. Nearly all granule cells were immuno-positive for Cox-2, whereas the CA3 and hilus sectors showed no remarkable increase in immunoreactive cell numbers. In sham-operated animals exposed to long-term hypothermia - but not ischemia, Cox-2 staining profiles were similar to those in the control animals. These results suggest that, for a drastic increase in Cox-2 immunoreactive granule cells to occur within a short time period (4 h), at a minimum, both hypothermia and ischemia, are required. Considering the neuroprotective roles of the hypothermia, a rapid increase in Cox-2 in the dentate gyrus might be associated with this temperature-sensitive phenomenon.

Interstitial cells of Cajal (ICC) are important regulatory cells generating electrical rhythmicity and transducing neural signals in the gastrointestinal musculature. ICC express the proto-oncogene c-kit, a receptor tyrosine kinase, and can be examined morphologically using the c-Kit antibody. The c-kit gene is allelic with the murine white-spotting locus W, and the c-kit mutation (W mutation) affects various aspects of hematopoietic cells, germ cells, melanocytes, mast cells, and ICC. Heterozygous W/W( v) mutant mice lack a specific type of ICC and have been used to reveal its function. To search for a new model that lacks a specific type of ICC, we examined homozygous W( v)/W( v) black-eyed-white mice that are viable with anemia. Results showed the principal patterns of ICC deficiency were the same between the W/W( v) and W( v)/W( v) mutants. In the stomach of both mice, intramuscular ICC (ICC-IM) were missing and myenteric ICC (ICC-MY) were reduced in number. In the small intestine, the number of ICC-MY was severely reduced in spite of a normal distribution of deep muscular plexus ICC (ICC-DMP). The cecum also exhibited fewer reduced. ICC-IM in the colon were almost entirely missing, whereas ICC-MY were reduced only in the distal colon. In the small intestine and colon, the number of remaining ICC-MY in W( v)/W( v) mice was greater than that in W/W( v) mice. The enteric nervous system of the two mutant mice showed normal characteristics. From these findings, we conclude that W( v)/W( v) mice represent a new genotype that lacks a part of the ICC in its gastrointestinal musculature.