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M C Pierson

Publications and source records attributed to M C Pierson.

5 recordsLinked to original sources
PubMed1993

Interleukin-1 beta and transforming growth factor-alpha/epidermal growth factor induce expression of M(r) 95,000 type IV collagenase/gelatinase and interstitial fibroblast-type collagenase by rat mucosal keratinocytes.

Rat mucosal keratinocytes serially propagated under permanently serum-free conditions responded to interleukin (IL)-1 beta/IL-alpha and to transforming growth factor (TGF)-alpha/epidermal growth factor (EGF) (as well as to 12-O-tetradecanoylphorbol-13-acetate (TPA)) by upregulation of M(r) 95,000 gelatinase (MMP-9) (M(r) 95K GL) and fibroblast-type collagenase (MMP-1) (FIB-CL), whereas control cells expressed barely detectable levels of either of these enzymes. The cells secreted 8-10 micrograms/10(6) cells/day (M(r) 95K GL) and 2-3 micrograms/10(6) cells/day (FIB-CL) of enzyme protein for at least 24 h when maximally induced. This level was attained only after a 24-h lag period, and the earliest emergence of enzyme protein in the culture medium required 10-14 h. IL-1 beta was by far the most potent cytokine with maximal effect already at 10(-10) M, whereas IL-1 alpha, TGF-alpha, and EGF required 20-100-fold higher concentrations. Pretreatment of the cells with TPA (10(-7) M) abolished the subsequent response to IL-1 beta, TGF-alpha, and EGF and at the same time resulted in > 90% reduction of cytosolic protein kinase C activity. Surprisingly, staurosporine, a potent kinase inhibitor, not only failed to block growth factor/cytokine responses but itself stimulated expression of the enzymes at a magnitude comparable to TPA. The inducing effect of TGF-alpha/EGF was down-regulated by 70-85% by 10(-7) M dexamethasone. Dexamethasone was less effective in ablating the IL-1 beta response yielding 60% reduction M(r) 95K GL and little or no reduction of FIB-CL. Dexamethasone also failed to block the TPA response.

Alkaloids↗
PubMed1992

Degradation of collagen fibrils by live cells: role of expression and activation of procollagenase.

We have examined the conditions for dissolution by live cells of an extracellular matrix composed of reconstituted type I collagen fibrils, using three different cell types which express varying constitutive or inducible levels of procollagenase and collagenase inhibitor. The two major conclusions from these studies were that (i) expression of collagenase is a necessary but not sufficient requirement for dissolution of the collagen fibrils and that (ii) activation of procollagenase is a rate-limiting step. Cells which secreted high levels of procollagenase dissolved collagen fibrils only to the extent that they were able to activate the enzyme. Cells which also expressed inhibitor failed to activate procollagenase in the culture medium and did not dissolve the collagen fibrils unless procollagenase-activation was assisted by exogenous proteinase activity. Cells that did not express inhibitor ultimately did activate procollagenase but the process was slow and incomplete. Introduction of exogenous proteinase activity either in the form of plasminogen, plasmin, or trypsin stimulated collagen breakdown by several fold. Analysis of the culture medium sampled from such cultures showed that the stimulating effect of exogenous proteinases could be ascribed to three separate, but synergistic events: elevated expression of procollagenase, conversion of procollagenase to active form and inactivation of collagenase inhibitor. Two lines of evidence suggested that the dissolution of collagen fibrils in these cultures was mediated by a collagenase-dependent pathway: (i) the rate of dissolution closely mirrored the level of expression of collagenase and (ii) the process was blocked by inhibitory collagenase-specific antibodies.

Adult↗
PubMed1988

Specific binding proteins for selenium in rat tissues.

The preventive and therapeutic potential of selenium (Se), a micronutrient, against cancer has been well documented in several test systems, but the mechanism of its action is not known. The possibility that Se might function in a manner similar to steroid hormones and retinoids through mediation of cellular receptors was examined. A specific 2S cellular binding protein (SeBP) for Na2[75Se]O3 was detected in rat tissue extracts. Liver and intestine exhibited highest levels of SeBP, and heart, uterus and spleen had the lowest levels. Oral administration of Na2[75Se]O3 to rats resulted in its uptake by the tissues with concomitant appearance of [75Se]SeBP complex. The protein binds sodium selenite with moderately high affinity; the apparent dissociation constant was determined by Scatchard analysis to be 1.1 X 10(-7) M. SeBP focused at pH 5.3 upon isoelectric focusing in ampholines of pH 3-10. Competitive binding affinity studies with unlabeled test compounds revealed that selenium dioxide and selenocystine showed high binding affinity (90-95%) for the selenite-binding site on SeBP. Sodium selenate, elemental Se powder, and selenomethionine, however, showed poor competition with sodium selenite. Biological activity of the above selenocompounds, as expressed by others, correlate with their binding affinities for SeBP. Sodium sulfite showed 35% inhibition of Na2[75Se]O3 binding, but sulfate showed none. Two ultimate carcinogens, N-methyl-N-nitrosourea and N-methyl-N'-nitro-N-nitrosoguanidine, and two retinoids, retinol and retinoic acid, showed less than 10% inhibition of binding. Interaction of Se with SeBP is completely blocked by thiol inhibitors. Plasma transport of Na2[75Se]O3 is mediated by a protein with a mol. wt of 68,000, which is presently identified, by immunoprecipitation studies as well as by Affi-Gel Blue column chromatographic experiments, as serum albumin. The results suggest that the plasma transport of Se is facilitated by albumin, and that the intracellular transport of Se for its biological functions is accomplished by SeBP.

Animals↗
PubMedDate not supplied

Persistent expression of a soluble form of Fas/APO1 in continuously activated T cells from a patient with SLE.

OBJECTIVE: To report a patient with SLE whose T cells expressed disproportionally increased amounts of an alternatively spliced form of Fas/APO1 transcript and secreted a soluble form of Fas. METHODS: We established continuously activated, short-term T cell lines from 16 patients with SLE and from 6 normal controls. The structure, expression and function of Fas was examined using RT-PCR and sequencing, flow cytometry (surface expression of Fas), ELISA (measurement of soluble Fas) and a PI-based cytotoxicity assay (functional analysis). RESULTS: A soluble form of Fas which originates from an alternatively spliced transcript and lacks the transmembrane domain of the original molecule was the dominant product of the Fas-gene in one line (S18B) derived from a patient with very active SLE. Compared to a control line, the S18B cells displayed decreased surface Fas expression but increased accumulation of Fas inside the cell. The amount of soluble Fas in the culture supernatant of S18B was found to be 1.8 times higher than that of a control line. Culture supernatants from S18B cells inhibited anti-Fas mAb-medicated T cell death. CONCLUSION: Continuously activated T cells from one patient with SLE displayed increased amounts of soluble Fas that inhibits anti-Fas mediated cell death. Although the frequency of this abnormality among patients with SLE and other diseases is unknown, increased production of soluble Fas may have contributed to the pathogenesis of SLE in the patient presented here.

Adolescent↗