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Biomedical subjects

D N Sauder

Publications and source records attributed to D N Sauder.

At least 109 records · Page 6Linked to original sources
PubMed1991

Augmentation of granulocyte/macrophage colony-stimulating factor expression by ultraviolet irradiation is mediated by interleukin 1 in Pam 212 keratinocytes.

Keratinocytes are a potent source of a variety of cytokines including granulocyte-macrophage colony-stimulating factor (GM-CSF). In this study, we have shown that ultraviolet B (UVB) irradiation augments GM-CSF mRNA expression by murine keratinocytes. This is reflected in the increased production of GM-CSF protein by these cells. In the same cell population, exposure to UVB irradiation increases interleukin 1 alpha (IL-1 alpha) mRNA and IL-1 protein as detected by bioactivity. This increase in IL-1 alpha precedes the increase of GM-CSF mRNA. Addition of recombinant IL-1 alpha to the medium increases GM-CSF mRNA expression. Anti-IL-1 alpha antibodies can completely inhibit UV-augmented GM-CSF mRNA expression. These results demonstrate that UVB irradiation-induced augmentation of GM-CSF is mediated by UV-induced IL-1 alpha.

Animals↗
PubMed1991

Regulation of GM-CSF and IL-3 production from the murine keratinocyte cell line PAM 212 following exposure to ultraviolet radiation.

Ultraviolet radiation (UVR) exposure induces profound changes in the synthesis and secretion of various cytokines both in vivo and in vitro. Little is known regarding the mechanism of these responses. This investigation evaluated the effects of UVR on the ability of a murine keratinocyte line (PAM 212) to produce interleukin 3 (IL-3) and granulocyte-macrophage colony stimulating factor (GM-CSF). Subconfluent rapidly dividing PAM 212 cells were shown by RNA slot-blot hybridization studies to have increased levels of mRNA for both IL-3 and GM-CSF within 1 h of UVR exposure. However, only GM-CSF-specific bioactivity, as determined by antibody neutralization studies, was shown to increase above baseline in cell supernatants. Cells grown to confluence responded differently to UVR. Under these culture conditions an apparent decrease in bioactivity was detected after UVR exposure for both growth factors, and no change in mRNA levels was detected. In addition to culture density, removal of extracellular calcium or sodium during irradiation, treatment with amiloride, or inhibition of new mRNA synthesis with cordycepin was shown to influence the UVR-induced alteration in release of IL-3 or GM-CSF bioactivity from both confluent and subconfluent PAM 212 cells. These results demonstrate that UVR influences the release of the colony stimulating factors GM-CSF and IL-3 from keratinocyte, and suggests that the state of cell growth and conditions of membrane ion transport influence the mechanisms regulating secretion of those factors.

Animals↗
PubMed1990

Fetal bovine serum contains an inhibitor of interleukin-1.

The keratinocyte cell line COLO-16 constitutively produces factors with interleukin-1 (IL-1) activity including IL-1 alpha and IL-1 beta. IL-1 activity assayed by thymocyte proliferation from cell supernatants was 20-50% less if cells were maintained in media containing 10% fetal bovine serum (FBS) compared to media without serum 24 h prior to harvest. The increased IL-1 activity in supernatants from cells in serum free media was not due to increased cellular levels of IL-1 alpha or IL-1 beta mRNA. Similarly, IL-1 activity recovered from conditioned supernatants of COS cells transfected with expression vectors containing IL-1 beta cDNA was approximately 22-45% less in cells grown in 20% FBS medium compared to similar cultures grown for 3 days post transfection in 1% FBS. When serial dilutions of recombinant IL-1 were made in buffer containing 10% FBS and assayed by a thymocyte proliferation method, a 30-50% decrease in activity was observed. IL-1 activity was also measured by its ability to induce prostaglandin E2 synthesis by fibroblasts. When COS conditioned supernatants were applied to fibroblast cultures there was 30% less prostaglandin E2 activity from fibroblasts treated with COS supernatants containing 20% FBS, compared to supernatants containing 1% FBS. The inhibitor molecule was partially purified by gel filtration and found to have a molecular weight of approximately 85,000. The presence of FBS in cell-conditioned media significantly reduces the sensitivity of IL-1 detection by bioassay techniques.

Animals↗
PubMed1990

IL-1 activity is reduced in psoriatic skin. Decreased IL-1 alpha and increased nonfunctional IL-1 beta.

IL-1 may influence or be influenced by a number of abnormalities present in psoriasis; including keratinocyte proliferation, eicosanoid production, fibroblast activation, endothelial cell adhesiveness, T cell infiltration and activation, cyclic nucleotide metabolism, and transmembrane signal transduction mechanisms. We assessed IL-1 regulation in normal, uninvolved, and involved skin of psoriatic patients using immunofluorescence microscopy, a sensitive ELISA method to quantitate immunoreactive IL-1 beta and IL-1 alpha protein levels, the thymocyte proliferation costimulation assay, costimulation of the LBRM.33 IL-1-sensitive cell line, and Northern blotting of cellular RNA to quantitate IL-1 alpha and beta mRNA. IL-1 beta was easily detectable by immunofluorescence microscopy and found to be localized predominantly in epidermal keratinocytes, whereas IL-1 alpha was not detectable with this method. Immunoreactive IL-1 beta was found to be elevated in cytosolic extracts derived from involved psoriatic keratomes relative to keratomes of normal skin. The elevated IL-1 beta protein was accompanied by elevated levels of IL-1 beta mRNA in psoriatic skin relative to normal skin. In contrast, immunoreactive IL-1 alpha levels were markedly reduced in lesional psoriatic skin. In functional assays using both the thymocyte proliferation assay and the LBRM.33 cell line, IL-1 activity from psoriatic involved skin keratomes was markedly reduced relative to that of uninvolved psoriatic keratomes and normal skin. All activity of both normal and psoriatic skin was attributable to IL-1 alpha. The elevated IL-1 beta immunoreactive protein present in psoriatic skin was found to be functionally inactive in these assays. The inactivity of the IL-1 beta was not due to an artifact of the cytosolic method of preparation because IL-1 beta released by psoriatic skin into the media was also nonfunctional. This was in keeping with the demonstration that the IL-1 beta was nonfunctional despite existing as a processed molecule. Taken together, these data demonstrate uncoordinated regulation of IL-1 alpha and Il-1 beta in psoriasis. The profound and complex changes in this system suggest IL-1 dysregulation may be integrally involved in the inflammatory, biochemical, and proliferative processes involved in the pathophysiology of psoriasis.

Biological Assay↗
PubMed1990

Pretibial epidermolysis bullosa: report of a case.

Pretibial epidermolysis bullosa is a rare variant of hereditary epidermolysis bullosa that is characterized by the delayed onset of a blistering eruption limited to the pretibial area. We present a case in a 48-year-old woman. Immunofluorescence mapping demonstrated blister formation below the basement membrane. This was confirmed by ultrastructural investigations that also revealed rudimentary anchoring fibrils similar to those described in the dominant dystrophic forms of epidermolysis bullosa.

Basement Membrane↗
PubMed1990

The role of epidermal cytokines in inflammatory skin diseases.

Cytokines (hormone-like polypeptide mediators) play a major role in inflammatory and immunoregulatory responses. Skin, and particularly keratinocytes in the skin, represent a potent source for many cytokines, including interleukins 1, 6, 8, and the hemopoietic colony stimulating factors. Cytokines initiate their biologic action by interacting with target cells bearing cytokine receptors and then initiating a cascade of cellular interactions. Certain inflammatory skin diseases have been associated with overproduction of cytokines, alteration in cytokine receptors, or dysregulation of cytokines. While data is still quite preliminary, it is likely that cytokines contribute to the pathogenesis of many inflammatory skin diseases.

Cytokines↗
PubMed1990

Expression and modulation of nerve growth factor in murine keratinocytes (PAM 212).

Nerve growth factor (NGF) is a polypeptide that is required for normal development and maintenance of the sympathetic and sensory nervous systems. Skin has been shown to contain relatively high amounts of NGF, which is in keeping with the finding that the quantity of NGF in a tissue is proportional to the extent of sympathetic innervation of that organ. Since the keratinocyte, a major cellular constituent of the skin, is known to produce other growth factors and cytokines, our experiments were designed to determine whether keratinocytes are a source of NGF. Keratinocyte-conditioned media from the keratinocyte cell line PAM 212 contained NGF-like activity, approximately 2-3 ng/ml, as detected by the neurite outgrowth assay. Freshly isolated BALB/c keratinocytes contained approximately 0.1 ng/ml. Using a cDNA probe directed against NGF, we demonstrated the presence of a 1.3-kb NGF mRNA in both PAM 212 and BALB/c keratinocytes. Since ultraviolet radiation (UV) is a potentially important modulating factor for cytokines in skin, we examined the effect of UV on NGF mRNA expression. Although UV initially inhibited the expression of keratinocyte NGF mRNA (4 h), by 24 h an induction of NGF mRNA was seen. The NGF signal could also be induced by phorbol esters. Thus, keratinocytes synthesize and express NGF, and its expression is modulated by UVB and phorbol esters.

Animals↗
PubMed1990

Interleukin-1 enhances epidermal wound healing.

Previous in vitro studies suggest that the interleukin-1 (IL-1) proteins may be important for skin function. Keratinocytes are known to synthesize IL-1 in response to injury and IL-1 has been shown to stimulate fibroblast and keratinocyte growth, collagen synthesis by fibroblasts, and chemotaxis of keratinocytes. In order to evaluate the ability of IL-1 to enhance wound healing, recombinant human IL-1 alpha was applied topically in a water-miscible cream to partial thickness wounds made on the backs of pathogen-free adult pigs. The wounded site was excised at various times for assessment of epidermal regeneration. This study shows a statistically significant enhancement of healing of the IL-1-treated wounds compared with either air-exposed or vehicle-treated wounds. Histologic examination of biopsies from IL-1-treated wounds indicated complete and architecturally normal epidermal regeneration. Porcine keratinocytes and membranes prepared from porcine skin were found to possess high affinity receptors for human IL-1 alpha. This study suggests that topical administration of IL-1 may be useful for the promotion of wound healing.

Administration, Cutaneous↗
PubMed1990

Keratinocyte cytokines and growth factors. Functions in skin immunity and homeostasis.

Evidence has been presented to support the theory that the KC, by virtue of its production of cytokines and growth factors, is an integral component of the immune system. The production of cytokines by the KC is normally carefully regulated in order to maintain normal body homeostasis. Malfunction of the regulatory processes controlling cytokine release may result in the development of skin disease.

Cell Division↗
PubMed1990

Expression of interleukin-1 beta in a human keratinocyte cell line.

The human keratinocyte cell line COLO-16 expresses mRNA homologous to human IL-1 alpha and IL-beta (transcript sizes 2.3 and 1.6 kb, respectively). A 1.2 kbp cDNA was selected with a human IL-1 beta probe from a lambda gt11 library constructed using poly A+ RNA from COLO-16 cells. Sequence analysis revealed that this cDNA was nearly identical to the 3' 1.2 kb of human monocyte IL-1 beta. When this cDNA was expressed in COS cells using a mammalian expression vector, IL-1 activity was detected in the cell conditioned supernatants using assays for D10-T-cell, thymocyte and fibroblast proliferation. Western analysis of lysates from COS cells transfected with this clone revealed the presence of a -17 kDa protein which reacted with antisera to human IL-1 beta. This protein was the same size as the processed form of IL-1 beta present in COLO-16 cells suggesting that this cDNA encodes the mature form of IL-1 beta. COLO-16 cells contain proteins of -30 kDa and 17 kDa which are immunoreactive with specific antisera for human IL-1 alpha and human IL-1 beta. Despite the presence of four-fold greater amounts of immunoreactive IL-1 beta protein than IL-1 alpha in cell lysates, all the IL-1 activity in the lysate could be neutralized by antisera to IL-1 alpha. IL-1 beta comprised only 25% of the IL-1 activity in the cell-conditioned media, all remaining activity was neutralized by antisera to IL-1 alpha. Whereas IL-1 alpha protein in both cell lysates and conditioned supernatants was predominantly in the processed -17 kDa form, IL-1 beta proteins were primarily of the processed and inactive 30kDa species. This apparent inability of keratinocytes to process IL-1 beta may explain our observations that the IL-1 activity secreted by COLO-16 cells is principally due to IL-1 alpha.

Amino Acid Sequence↗
PubMed1989

A new role for epidermal cell-derived thymocyte activating factor/IL-1 as an antagonist for distinct epidermal cell function.

It is known that many immunologic responses to IL-1 are antagonized by the neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH). This led us to investigate the possible reciprocal effects of IL-1 and the functionally related epidermal cytokines, epidermal cell-derived thymocyte activating factor (ETAF) and IL-6, on the melanogenic effect of alpha-MSH on murine Cloudman melanoma cells. When these cells were treated with ETAF in combination with alpha-MSH or its potent analog [Nle4,D-Phe7]-alpha-MSH, the melanotropin induced increase in tyrosinase activity, and thus melanin synthesis, was abrogated. This inhibitory effect of ETAF was not mediated by competitive binding to the melanotropin receptor, because ETAF also blocked the melanogenic response of melanoma cells to isobutyl methylxanthine (IBMX) and to PGE1 and PGE2. ETAF had no effect on cellular proliferation. Inhibition of the stimulated tyrosinase activity by ETAF was not due to diminished cAMP synthesis or increased cAMP degradation. Cells treated concomitantly with ETAF and alpha-MSH, IBMX, or PGE1 had the same cAMP levels as cells treated with alpha-MSH, IBMX, or PGE1 alone. In contrast to ETAF, human rIL-1 alpha or IL-1 beta alone or in combination did not have an inhibitory effect on melanogenesis. IL-6 significantly inhibited the basal level of tyrosinase and partially abrogated the alpha-MSH-induced tyrosinase activity. IL-6 also stimulated cellular proliferation when added alone or in combination with alpha-MSH. Granulocyte-macrophage colony stimulating factor (GM-CSF) did not alter either the tyrosinase activity or cellular replication at the concentrations tested. IL-1 alpha, GM-CSF, and IL-6 or IL-1 alpha and GM-CSF added together did not significantly affect the MSH-induced tyrosinase activity. These results ascribe a new potential function for ETAF and IL-6 as modulators of the melanogenic response of pigment cells.

1-Methyl-3-isobutylxanthine↗
PubMed1989

Effect of age on cutaneous interleukin 1 expression.

Age-related changes in epidermal immune function include morphologic and functional changes in Langerhans cells and decreased epidermal cytokine activity. In this study, expression of interleukin 1 (IL-1) mRNA was quantitated in 6-102-week old mice of different strains. A significant decline in cutaneous IL-1 expression occurred in mice of all strains examined; the rate of decline was most prominent in MRL/MpJ+ mice who also had highest initial levels of IL-1. This observation is in keeping with previous observations that the quantity of several gene products in youth is directly proportional to the rate of change of the quantity of that gene product. The term "economic correction" is used to describe this phenomenon.

Aging↗
PubMed1989

Economic correction; quantity and age-related rate of change.

Correlation between the relative magnitude of activity or concentration in youth and the relative magnitude of age-related decrease occurs in several systems. We have observed this correlation in density of D2-dopamine receptors of the striatal membrane, activity of lymphocyte activated killer cells, relative density of CD8 on thymocytes, augmenting activity of T splenocytes and mRNA, coding for IL-1 in Langerhans cells. We have suggested that this correlation should be considered in the context of balanced investment in lifespan and reproductive efficiency, that it may be the result of feedback regulation and have designated it as "economic correction".

Age Factors↗
PubMed1989

Human interleukin-1 alpha is chemotactic for normal human keratinocytes.

Interleukin-1 (IL-1) has been shown to have mitogenic and chemotactic properties for a variety of cell types includes keratinocytes. These studies suggested that keratinocytes possess receptors for IL-1. In this study, the chemotactic properties of IL-1 for keratinocytes were confirmed and IL-1 receptors were demonstrated on keratinocytes using a radio receptor assay. Crosslinking studies with IL-1 alpha identified two major bands of Mr 97 kDa and 133 kDa. Thus, keratinocytes possess high affinity IL-1 receptors and respond to IL-1 by directed migration.

Cells, Cultured↗
PubMed1989

Interleukin 1.

The last decade has witnessed a remarkable expansion in the understanding of the skin as an immunologic organ. A prime example of this is the discovery that keratinocytes can synthesize and secrete immunoregulatory and proinflammatory glycoproteins termed cytokines. Initial studies focused on interleukin 1-like molecules produced by keratinocytes, initially termed epidermal cell-derived thymocyte activating factor (ETAF). It is now clear that the functional activities described by the term ETAF are composed mainly of interleukin 1 alpha and interleukin 1 beta, although other epidermal cytokines may contribute to the biologic activity. The biologic properties of interleukin 1 are the basis of this review.

Animals↗