Immunocytochemical demonstration of calmodulin in cells secreting by exocytosis

Summary Calmodulin is a regulator of several calcium-dependent cellular processes. It has been suggested that it plays a role in the mechanism of secretion. Employing an indirect immunoperoxidase technique at the light microscope level, this study demonstrates the presence of calmodulin in several exocytotic cells (mast cells, thyroid follicular cells, neurohypophyseal neurosecretory terminals, pancreatic-cells and pancreatic acinus cells) in rat and man. The positive staining reaction for calmodulin was granular and at least in the case of rat mast cells it appeared to be associated with the granule membrane.     

Inhibition of interleukin-1 beta release from cultured human peripheral blood mononuclear cells by prednisolone

Prednisolone, a water-soluble glucocorticoid hormone, suppressed the secretion of interleukin-1 beta from human peripheral blood mononuclear cells in culture. The prednisolone-induced suppression of the monokine release was dose-related and the half maximal response was observed at 0.1 nM.     

Morphological evidence of a polypeptide-like secretory function of the B cells in the mouse synovial membrane

Summary In the synovial membrane of the mouse, morphological features associated with acitve secretion are unusually well developed in cells immediately subjacent to the lining layer (in the position of B cells), comparable to those of cells known to elaborate polypeptides.This work was supported by grant No 74.1.133.4, Institut National de la Santé et de la Recherche Médicale, France.     

Regulation of the type III InsP3 receptor and its role in beta cell function

The type III inositol 1,4,5-trisphosphate receptor (InsP3R) is an important intracellular calcium (Ca2+) release channel in the pancreatic beta cell. Pancreatic beta cells secrete insulin following a characteristic change in membrane potential that leads to an increase in cytoplasmic Ca2+. Both extracellular Ca2+ and Ca2+ mobilized from InsP3-sensitive stores contribute to this increase. RIN-m5F cells, an insulin-secreting beta cell line, preferentially express the type III InsP3R. These cells have been useful in determining the regulatory properties of the type III InsP3R and the role of this isoform in an intact cell. The type III InsP3R is ideal for signal initiation because high cytoplasmic Ca2+ does not inhibit its activity. Altered insulin secretion, the result of changes in Ca2+ handling by the beta cell, has significant clinical consequences.     

Persistance of endocrine cells in immuno-induced carcinoma of the exocrine pancreas: insulin, glucagon, and somatostatin cells]

In immuno-induced exocrine pancreatic carcinomas, which keep their exocrine secretory specificity through their different evolution stages [(1), (2)], normal B, A and D endocrine cells are still found, demonstrated by immunochemical techniques. They are localized in the islets of Langerhans. B and A cells are scattered in adenomatous pancreatic remains, and in the anaplasic carcinoma; D cells are found in the ductular and adenomatous remains. The three types of endocrine secretion granules are analyzed by electron microscopy at the early and late stages of carcinogenesis. The origin of the persisting endocrine cells and the nature of undifferentiated cells proliferating from the ductular epithelium are discussed.     

Breaking T cell tolerance to beta cell antigens by merocytic dendritic cells

In type 1 diabetes (T1D), a break in central and peripheral tolerance results in antigen-specific T cells destroying insulin-producing, pancreatic beta cells. Herein, we discuss the critical sub-population of dendritic cells responsible for mediating both the cross-presentation of islet antigen to CD8⁺ T cells and the direct presentation of beta cell antigen to CD4⁺ T cells. These cells, termed merocytic dendritic cells (mcDC), are more numerous in non-obese diabetic (NOD), and antigen-loaded mcDC rescue CD8⁺ T cells from peripheral anergy and deletion, and stimulate islet-reactive CD4⁺ T cells. When purified from the pancreatic lymph nodes of overtly diabetic NOD mice, mcDC can break peripheral T cell tolerance to beta cell antigens in vivo and induce rapid onset T cell-mediated T1D in young NOD mouse. Thus, the mcDC subset appears to represent the long-sought critical antigen-presenting cell responsible for breaking peripheral tolerance to beta cell antigen in vivo.     

Pharmacology and function of the myoepithelial cell in the eccrine sweat gland.

Both acetylcholine and a Ca-ionophore, A23187, are comparatively strong stimulants of eccrine sweat secretion in vitro. Nevertheless, the contraction of the secretory coil was seen only after stimulation with acetylcholine but not with alpha or beta adrenergic drugs or with A23187. It was thus inferred that the myoepithelial contraction may not be playing an indispensable role in the overall process of eccrine sweat secretion.     

Induction of lymphokine-activated killer cells from nude mouse spleen cells by interleukin-4

The induction of lymphokine-activated killer (LAK) cells from natural killer (NK) lineage cells by interleukin-4 (IL-4) was studied in vitro. Activation of nude mouse spleen cells by IL-4 generated cytotoxic cells, capable of killing NK-sensitive as well as NK-resistant tumor cells. The induction of peak lytic activity was demonstrated after 3 days of culture with IL-4. Surface marker analysis indicated that the majority of precursor cells were aGM1⁺, Thy1^–, and the majority of effector cells were aGM1⁺, Thy1⁺, suggesting that IL-4 induced LAK cells from nude mouse spleen cells were similar to those from normal mouse spleen cells. The induction of nude mouse LAK cells by IL-4 was partially inhibited by anti-IL-4 or anti-interferon (IFN)-, antibody, and it was further inhibited by the combination of two antibodies, suggesting that IFN-, production was associated with LAK induction of NK lineage cells by IL-4.     

Pharmacology and function of the myoepithelial cell in the eccrine sweat gland

Summary Both acetylcholine and a Ca-ionophore, A23187, are comparatively strong stimulants of eccrine sweat secretion in vitro. Nevertheless, the contraction of the secretory coil was seen only after stimulation with acetylcholine but not with alpha or beta adrenergic drugs or with A23187. It was thus inferred that the myoepithelial contraction may not be playing an indispensable role in the overall process of eccrine sweat secretion.Acknowledgment. The present study was supported by NIH grant 2R01AM 1625804.     

Effects of glucagon and insulin on the Paneth cells of the mouse duodenum.

The effect of glucagon and insulin on the paneth cells (PC) of the duodenum of the mouse was investigated using light microscopy. Both glucagon and insulin were able to increase significantly the number of the secretory granules of PC. This possibly means that these hormones are capable of inhibiting the secretion of PC.     

Induction of hemopoietic chimerism in the caprine fetus by intraperitoneal injection of fetal liver cells

Summary Intraperitoneal injection of allogeneic liver cells from 43-day-old male fetuses into normal 60-day female goat fetuses resulted in persistent hemopoietic chimerism in surviving recipients without clinical evidence of graft-versus-host disease. Transplantation of normal fetal liver cells into preimmunocompetent goat fetuses affected with -D-mannosidosis may provide an alternative strategy for evaluating hemopoietic stem cell transplantation in the treatment of human lysosomal storage diseases.     

Immunocytochemical demonstration of calmodulin in cells secreting by exocytosis

Calmodulin is a regulator of several calcium-dependent cellular processes. It has been suggested that it plays a role in the mechanism of secretion. Employing an indirect immunoperoxidase technique at the light microscope level, this study demonstrates the presence of calmodulin in several exocytotic cells (mast cells, thyroid follicular cells, neurohypophyseal neurosecretory terminals, pancreatic beta-cells and pancreatic acinus cells) in rat and man. The positive staining reaction for calmodulin was granular and at least in the case of rat mast cells it appeared to be associated with the granule membrane.     

Functional inhibition of isolated pancreatic cells, new technic for the detection of macrophage cytotoxicity]

It is usually accepted that macrophages "activated" by lymphokines may be found cytotoxic against tumoral target cells but show no detectable cytotoxicity in in vitro tests using normal non tumoral cells as target cells. These data have been obtained mainly with the chromium-release test. The present paper describes a new test using normal isolated pancreatic cells as target cells and evaluating the effect of activated or non-activated macrophages on the insulin secretion response to glucose stimulation. The results show a striking decrease in this response following an 18-hr incubation of pancreatic islet cells with activated macrophages, as compared to that of the same cells incubated with control macrophages. This is clear evidence that activated macrophages may alter normal cells and suggests that their cytotoxic properties are not restricted to tumoral target cells.     

Morphological aspects of chemically stimulated bovine chromaffin cells

Summary Isolated bovine chromaffin cells were chemically stimulated. The resulting appearance of local changes in membrane structure were compared with the integration of granular proteins into the cell membrane as seen after binding of fluorescence labeled anti-dopamine--hydroxylase. Protuberances of the cell membrane which can be perceived by Nomarski contrast optics are largely congruent with local tracer accumulations at the cell surface.     

Suppressor of cytokine signaling-1 inhibits caspase activation and protects from cytokine-induced beta cell death

Pancreatic beta cell damage caused by pro-inflammatory cytokines interleukin-1β (IL-1β), interferon-γ (IFNγ) and tumor necrosis factor-α (TNFα) is a key event in the pathogenesis of type 1 diabetes. The suppressor of cytokine signaling-1 (SOCS-1) blocks IFNγ-induced signaling and prevents diabetes in the non-obese diabetic mouse. Here, we investigated if SOCS-1 overexpression in primary beta cells provides protection from cytokine-induced islet cell dysfunction and death. We demonstrate that SOCS-1 does not prevent increase in NO production and decrease in glucose-stimulated insulin secretion in the presence of IL-1β, IFNγ, TNFα. However, it decreases the activation of caspase-3, -8 and -9, and thereby, promotes a robust protection from cytokine-induced beta cell death. Our data suggest that SOCS-1 overexpression may not be sufficient in preventing all the biological activities of IFNγ in beta cells. In summary, we show that interference with IFNγ signal transduction pathways by SOCS-1 inhibits cytokine-stimulated pancreatic beta cell death.     

Relationships between neural crest cells and catecholamine in suckling mice

Summary In suckling mice injected i.p. with a 27 mg/kg dose of L-hydrochloric acid isoproterenol, multiple neural crest tumors developed and cell death of neural crest cells occurred. It is speculated that neural crest derivatives may be -receptor cells and contain regulatory units of neurotransmission mediated through cyclic AMP.     

Contraction of myoepithelial cells in secreting submandibular glands of dogs

Summary In slowly secreting submandibular glands of dogs, a sympathetic effect on myoepithelial cells was demonstrated as an acceleration of the flow, follwed by retardation, on short-lasting sympathetic stimulation, particularly after -adrenoceptor-blocking drugs.Supported by grant No. 14X-00539 from the Swedish Medical Research Council     

Isolation of human epidermal stem cells by adherence and the reconstruction of skin equivalents

The isolation of human epidermal stem cells is critical for their clinical applications. In the present study, we isolated three populations of epidermal keratinocytes according to their ability to adhere to collagen type IV: i.e., rapidly adhering (RA), slowly adhering (SA), and non-adhering (NA) cells. The aim of this study was to characterize RA cells and to investigate the possibility of using these cells for epidermis reconstruction. To identify RA cells, flow cytometric analysis was performed using anti-₆ integrin and anti-CD71 antibodies. RA cells express high levels of ₆ integrin and low levels of CD71, which are considered as markers of an epidermal stem cell nature. Furthermore, electron microscopy showed that RA cells are small and have a high nuclear to cytoplasmic ratio, whereas SA and NA cells have well-developed cellular organelles and abundant tonofilaments. Western blot analysis showed that RA cells are slow cycling and express p63, a putative epidermal stem cell marker, whereas SA and NA cells express c-Myc, which is known to regulate stem cell fate. To compare epidermal regenerative abilities, skin equivalents (SEs) were made using RA, SA, and NA cells. The epidermis constructed from RA cells was well formed compared to those formed from SA or NA cells. In addition, only SEs with RA cells expressed ₆ integrin and ₁ integrin at the basal layer. These results indicate that RA cells represent epidermal stem cells and are predominately comprised of stem cells. Therefore, the isolation of RA cells using a simple technique offers a potential route to their clinical application, because they are easily isolated and provide a high yield of epidermal stem cells.Received 2 July 2004; received after revision 20 August 2004; accepted 10 September 2004     

Purification of porcine granulosa cells by continuous Percoll gradient

Granulosa cells purified on a continuous Percoll gradient have considerably increased responsiveness to FSH in formation of cAMP, secretion of progesterone, and 125I[hCG] binding to cells incubated for 4 days in culture.