Regulation of macrophage and granulocyte proliferation. Specificities of prostaglandin E and lactoferrin

Hemopoietic colony-forming cells committed to macrophage differentiation (M-CFC) are selectively and differentially inhibited by prostaglandin E (PGE). A hierarchy of sensitivity was observed among murine CFC stimulated by colony-stimulating factors (CSF) which differ in their ability to initiate proliferation of morphologically distinct colony types, or stimulated by CSF provided by macrophage feeder layers. Inhibition of macrophage colony formation to 50 percent levels occurred with PGE concentrations between 10(-8) and 10(-9) M, and was still evident at 10(-10) -10(-11) M PGE concentrations. The growth of mixed colonies containing both macrophages and neutrophils was less sensitive to the inhibitory effects of PGE, however, the monocytoid component of these colonies was reduced in the presence of PGE. Neutrophil progenitor cell proliferation was not influenced by PGE concentrations below 10(-6) M, regardless of time of addition of PGE, whereas clonal macrophage expansion, as well as clone size, was sensitive to inhibition by PGE when added as late as 3 d after culture initiation. Prostaglandin F(2α), was not inhibitory to colony formation. Experimental evidence for a selective role of macrophage PGE in the regulation of macrophage colony formation was directly provided by utilizing resident peritoneal macrophages as a source of CSF for bone marrow target cell overlays. Simultaneous morphological analysis of colonies proliferating in bilayer culture in response to increasing concentrations of macrophages, and direct measurements of PGE synthesized by an identical number of macrophages maintained in liquid culture demonstrate that a specific decline in macrophage colony formation occurs coincident with a linear increase in macrophage PGE synthesis. Inhibition of macrophage PGE synthesis by indomethacin results in the specific enhancement of macrophage colony formation. Furthermore, macrophage PGE synthesis is induced by CSF preparations with the selective capacity to differentially stimulate macrophage proliferation, but not by those which preferentially stimulate granulocyte colony formation. In comparison to the effects of PGE on M-CFC, polymorphonuclear granulocyte-derived lactoferrin (LF) reduces macrophage production of colony-stimulating activities for macrophage, mixed macrophage- neutrophil and neutrophil colony formation. The ability of LF to reduce macrophage PGE synthesis, presumably by decreasing CSF production, suggests that LF and PGE can interact in the control of macrophage and granulocyte proliferation

Generation of host-directed and virus-specific antivirals using targeted protein degradation promoted by small molecules and viral RNA mimics.

Targeted protein degradation (TPD), as exemplified by proteolysis-targeting chimera (PROTAC), is an emerging drug discovery platform. PROTAC molecules, which typically contain a target protein ligand linked to an E3 ligase ligand, recruit a target protein to the E3 ligase to induce its ubiquitination and degradation. Here, we applied PROTAC approaches to develop broad-spectrum antivirals targeting key host factors for many viruses and virus-specific antivirals targeting unique viral proteins. For host-directed antivirals, we identified a small-molecule degrader, FM-74-103, that elicits selective degradation of human GSPT1, a translation termination factor. FM-74-103-mediated GSPT1 degradation inhibits both RNA and DNA viruses. Among virus-specific antivirals, we developed viral RNA oligonucleotide-based bifunctional molecules (Destroyers). As a proof of principle, RNA mimics of viral promoter sequences were used as heterobifunctional molecules to recruit and target influenza viral polymerase for degradation. This work highlights the broad utility of TPD to rationally design and develop next-generation antivirals

Genetic Polymorphism of Geranylgeranyl Diphosphate Synthase (GGSP1) Predicts Bone Density Response to Bisphosphonate Therapy in Korean Women

Purpose: Genetic factor is an important predisposing element influencing the susceptibility to osteoporosis and related complications. The purpose of the present study is to investigate whether genetic polymorphisms of farnesyl diphosphate synthase (FDPS) or geranylgeranyl diphosphate synthase (GGPS) genes were associated with the response to bisphosphonate therapy. Materials and Methods: In the present study, 144 Korean women with osteoporosis were included. Among 13 genetic polymorphisms found within the FDPS and GGPS1 gene, 4 genetic polymorphisms with frequencies > 5% were selected for further study. Bone mineral density (BMD) response after 1 year treatment of bisphosphonate therapy was analyzed according to the genotypes. Results: Women with 2 deletion allele of GGPS1 -8188A ins/del (rs3840452) had significantly higher femoral neck BMD at baseline compared with those with one or no deletion allele (0.768 +/- 0.127 vs. 0.695 +/- 0.090 respectively; p = 0.041). The response rate of women with 2 deletion allele of GGPS1 -8188A ins/del (28.6%) was significantly lower than the rate of women with one (81.4%) or no deletion allele (75.0%) (p = 0.011). Women with 2 deletion allele of GGPS1 -8188A ins/del had 7-fold higher risk of non-response to bisphosphonate therapy compared with women with other genotypes in GGPS1 -8188 after adjusting for baseline BMD (OR = 7.48; 95% CI = 1.3242.30; p = 0.023). Other polymorphisms in FDPS or GGPS1 were not associated with lumbar spine BMD or femoral neck BMD. Conclusion: Our Study suggested that GGPS1 -8188A ins/del polymorphism may confer susceptibility to femoral heck BMD response to bisphosphonate therapy in Korean women. However, further study should be done to confirm the results in a larger population.This work was supported by a grant from Ministry of Health, Welfare and Family of Korea (03-PJ10-PG13- GD01-0002).Guo RT, 2007, P NATL ACAD SCI USA, V104, P10022, DOI 10.1073/pnas.0702254104Gallagher JC, 2006, BONE, V39, P1268, DOI 10.1016/j.bone.2006.06.007Bonnick S, 2006, J CLIN ENDOCR METAB, V91, P2631, DOI 10.1210/jc.2005-2602BONNICK SL, 2006, AM J MED S1, V119, pS25Kim SW, 2005, ENDOCR J, V52, P667Palomba S, 2005, OSTEOPOROSIS INT, V16, P943, DOI 10.1007/s00198-004-1800-5Lewiecki EM, 2003, J CLIN DENSITOM, V6, P307Palomba S, 2003, CLIN ENDOCRINOL, V58, P365Qureshi AM, 2002, CALCIFIED TISSUE INT, V70, P158Turner CH, 2002, OSTEOPOROSIS INT, V13, P97Mann V, 2001, J CLIN INVEST, V107, P899Keen RW, 2001, RHEUMATOLOGY, V40, P48Bergstrom JD, 2000, ARCH BIOCHEM BIOPHYS, V373, P231Crilly RG, 2000, OSTEOPOROSIS INT, V11, P607Eisman JA, 1999, ENDOCR REV, V20, P788Tsukamoto K, 1999, J HUM GENET, V44, P148Keen RW, 1998, BONE, V23, P367Masi L, 1998, BIOCHEM BIOPH RES CO, V248, P190Uitterlinden AG, 1998, NEW ENGL J MED, V338, P1016Mizunuma H, 1997, BONE, V21, P379Kurland ES, 1997, J CLIN ENDOCR METAB, V82, P2799Shiraki M, 1997, J BONE MINER RES, V12, P1438Sainz J, 1997, NEW ENGL J MED, V337, P77Johnson ML, 1997, AM J HUM GENET, V60, P1326Langdahl BL, 1997, BONE, V20, P289SILVERMAN SL, 1992, CALCIFIED TISSUE INT, V50, P101

Dietary phytochemicals, HDAC inhibition, and DNA damage/repair defects in cancer cells

Genomic instability is a common feature of cancer etiology. This provides an avenue for therapeutic intervention, since cancer cells are more susceptible than normal cells to DNA damaging agents. However, there is growing evidence that the epigenetic mechanisms that impact DNA methylation and histone status also contribute to genomic instability. The DNA damage response, for example, is modulated by the acetylation status of histone and non-histone proteins, and by the opposing activities of histone acetyltransferase and histone deacetylase (HDAC) enzymes. Many HDACs overexpressed in cancer cells have been implicated in protecting such cells from genotoxic insults. Thus, HDAC inhibitors, in addition to unsilencing tumor suppressor genes, also can silence DNA repair pathways, inactivate non-histone proteins that are required for DNA stability, and induce reactive oxygen species and DNA double-strand breaks. This review summarizes how dietary phytochemicals that affect the epigenome also can trigger DNA damage and repair mechanisms. Where such data is available, examples are cited from studies in vitro and in vivo of polyphenols, organosulfur/organoselenium compounds, indoles, sesquiterpene lactones, and miscellaneous agents such as anacardic acid. Finally, by virtue of their genetic and epigenetic mechanisms, cancer chemopreventive agents are being redefined as chemo- or radio-sensitizers. A sustained DNA damage response coupled with insufficient repair may be a pivotal mechanism for apoptosis induction in cancer cells exposed to dietary phytochemicals. Future research, including appropriate clinical investigation, should clarify these emerging concepts in the context of both genetic and epigenetic mechanisms dysregulated in cancer, and the pros and cons of specific dietary intervention strategies