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Yong Li, John J Voorhees, Gary J FisherDepartment of Dermatology, University of Michigan, Ann Arbor, MI, USAType I collagen (COL1) is the predominant structural protein in the skin. COL1 forms densely packed fibrils which are essential for maintaining skin mechanical properties and youthful appearance.1 The enzyme matrix metalloproteinase-1 (MMP1) cleaves COL1 fibrils at a single site.2 Once cleaved by MMP1, COL1 fibrils can be degraded by other proteases. MMP1 expression is elevated during natural aging and chronic sun exposure, ie, photoaging, leading to excessive degradation of COL1.3 This excessive degradation contributes to COL1 deficiency in the skin of the elderly. COL1 deficiency impairs skin structural integrity and appearance.Given the detrimental role of MMP1 in mediating age-associated fragmentation of COL1 fibrils, it would be beneficial to include MMP1 inhibitors in topical antiaging skin care products. Naturally existing substances that are safe for human use, such as botanical extracts, are often used in skin care products. We have utilized highthroughput screening (HTS) to identify naturally existing MMP1 inhibitors that could be used for cosmetic purposes.

Production of inhibitor(s) of IL-1 activity can be induced in keratinocytes by exposure to UVB. We describe in this study the characterization of an endogenous constitutively expressed IL-1 inhibitor which is present in extracts of human psoriatic epidermal keratome biopsies. Size-fractionated extracts of normal human epidermis did not reveal IL-1 inhibitory factor(s) activity in normal epidermis. Psoriatic epidermal extracts, however, contained virtually no IL-1 bioactivity and inhibited the activity of recombinant human IL-1??. This IL-1 inhibitor has a molecular weight of approximately 30 kDa and a pI of 5.3, as revealed by fast protein liquid chromatography size fractionation and chromatofocusing of psoriatic epidermal extracts. IL-1 inhibitory activity was not blocked by neutralizing anti-TGF?? monoclonal antibody. It did not have any inhibitory effect upon normal cellular proliferation but could block the IL-1 induction of IL-2 production by LBRM. 33 cells as late as 4 h after exposure of LBRM. 33 cells to IL-1. Thus, in vivo human psoriatic epidermis expresses an IL-1 inhibitor that specifically inhibits IL-1 activity but which appears distinct from previously described UV-induced epidermal IL-1 inhibitory activity or TGF??

The BCL2 (B cell lymphoma/leukemia-2) proto-oncogene encodes a 26-kDa protein that has been localized to the inner mitochondrial membrane and that has been shown to enhance the survival of some types of hematopoietic cells. Here we show that NIH3T3 fibroblasts stably transfected with a BCL2 expression plasmid exhibit reduced dependence on competence-inducing growth factors (platelet-derived growth factor, PDGF; epidermal growth factor, EGF) for initiation of DNA synthesis. The importance of BCL2 for growth factorinduced proliferation of these cells was further confirmed by the useage of BCL2 antisense oligodeoxynucleotides. The mechanisms by which overexpression of p26 BCL2 contributes to fibroblast proliferation are unknown, but do not involve alterations in: (a) the production of inositol triphosphates (IP3), (b) PDGF-induced transient elevations in cytosolic Ca2+ ions, or (c) the activity of protein kinase C enzymes in these transfected cells. The results imply that changes in mitochondrial functions play an important role in the early stages of the cell cycle that render 3T3 cells competent to respond to the serum progression factors that stimulate entry into S-phase.

GTP-binding activity was fractionated into two peaks (GI and GII) by chromatography on heparin-agarose. GTP-dependent PLC activity eluted as a single peak, which co-chromatographed with GTP-binding peak GII. Rechromatography of peak GII on heparin-agarose, in the presence of 0.5% sodium cholate, resulted in separation of PLC and GTP-binding activities, and loss of GTP-dependent PLC activity. Recombining fractions containing PLC and GTP-binding activities restored GTP-dependent PLC activity. A specific GTP-binding protein of 29,000 daltons was identified in peak GII by Western blotting of column fractions with [[alpha]-32P]GTP. These results demonstrate that the soluble phospholipase C from human platelets is regulated by GTP S-binding protein (G29).