RESUMO
RATIONALE: Accumulating evidence indicates that stem/progenitor cells (SPCs) represent an important source of cells in atheromas and contribute to lesion formation and progression. OBJECTIVE: We investigated whether matrix metalloproteinase-8 (MMP8) played a role in SPC migration and their recruitment into atheromas. METHODS AND RESULTS: We found that SPCs in atheromas expressed MMP8 and that MMP8 knockout significantly reduced SPC numbers in atherosclerotic lesions in apolipoprotein E (ApoE)-deficient mice fed a Western diet. Further in vivo experiments showed that ApoE(-/-)/MMP8(-/-) mice injected with stem cells isolated from bone marrows of ApoE(-/-)/MMP8(-/-) mice had fewer SPCs in atheromas and smaller lesions than ApoE(-/-)/MMP8(-/-) mice injected with stem cells isolated from bone marrows of ApoE(-/-)/MMP8(+/+) mice. Ex vivo experiments showed that MMP8 deficiency inhibited the ability of SPCs to migrate from the arterial lumen and the adventitia into atherosclerotic lesions. In vitro assays indicated that MMP8 facilitated SPC migration across endothelial cells and through Matrigel or collagen I. We also found that MMP8 cleaved a-disintegrin-and-metalloproteinase-domain-10 and that MMP8 deficiency reduced mature a-disintegrin-and-metalloproteinase-domain-10 on SPCs. Knockdown of MMP8 or incubation with the a-disintegrin-and-metalloproteinase-domain-10 inhibitor GI254023X decreased E-cadherin shedding on SPCs. The decrease in migratory ability of SPCs with MMP8 knockdown was reduced by incubation of such cells with culture supernatant from SPCs without MMP8 knockdown, and this compensatory effect was abolished by an antibody against soluble E-cadherin. CONCLUSIONS: MMP8 plays an important role in SPC migration and their recruitment into atherosclerotic lesions.
Assuntos
Aorta/enzimologia , Doenças da Aorta/enzimologia , Aterosclerose/enzimologia , Movimento Celular , Metaloproteinase 8 da Matriz/metabolismo , Células-Tronco/enzimologia , Proteínas ADAM/antagonistas & inibidores , Proteínas ADAM/metabolismo , Animais , Antígenos Ly/metabolismo , Aorta/patologia , Doenças da Aorta/genética , Doenças da Aorta/patologia , Apolipoproteínas E/deficiência , Apolipoproteínas E/genética , Aterosclerose/genética , Aterosclerose/patologia , Biomarcadores/metabolismo , Caderinas/metabolismo , Células Cultivadas , Colágeno Tipo I/metabolismo , Dipeptídeos/farmacologia , Modelos Animais de Doenças , Células Endoteliais/enzimologia , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Ácidos Hidroxâmicos/farmacologia , Masculino , Metaloproteinase 8 da Matriz/deficiência , Metaloproteinase 8 da Matriz/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Placa Aterosclerótica , Inibidores de Proteases/farmacologia , Interferência de RNA , Transplante de Células-Tronco , Células-Tronco/efeitos dos fármacos , Células-Tronco/patologia , Fatores de Tempo , TransfecçãoRESUMO
Modulation of γ-secretase activity holds potential for the treatment of Alzheimer's disease. Most NSAID-derived γ-secretase modulators feature a carboxylic acid, which may impair blood-brain barrier permeation. The structure activity relationship of 33 carbazoles featuring diverse carboxylic acid isosteres or metabolic precursors thereof was established in a cellular amyloid secretion assay. The modulatory activity was observed for acidic moieties and metabolically labile esters only, which supports our hypothesis of an acid-lysine interaction to be relevant for this type of γ-secretase modulators.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Anti-Inflamatórios não Esteroides/síntese química , Carbazóis/síntese química , Ácidos/síntese química , Ácidos/química , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/patologia , Secretases da Proteína Precursora do Amiloide/química , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/efeitos dos fármacos , Precursor de Proteína beta-Amiloide/efeitos dos fármacos , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Anti-Inflamatórios não Esteroides/análise , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Carbazóis/análise , Carbazóis/química , Carbazóis/farmacologia , Ácidos Carboxílicos/análise , Ácidos Carboxílicos/síntese química , Ácidos Carboxílicos/química , Ácidos Carboxílicos/farmacologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Fenofibrato/análogos & derivados , Fenofibrato/química , Humanos , Camundongos , Terapia de Alvo Molecular , Relação Estrutura-AtividadeRESUMO
New ansamitocin derivatives were prepared by feeding aminobenzoic acid derivatives to cultures of Actinosynnema pretiosum HGF073, a mutant strain blocked in the biosynthesis of the required 3-amino-5-hydroxybenzoic acid (AHBA) starter unit. Use of several aminobenzoic acids as precursors led to a spectrum of products, reflecting the sequence of post-PKS tailoring steps involved in the generation of ansamitocins and adding novel aspects to the published suggestion model of post-PKS tailoring logic and flexibility. The studies provide insights into the substrate flexibility of the enzymes required for ansamitocin biosynthesis in A. pretiosum, whereas preliminary biological testing of the derivatives isolated and fully characterized by NMR spectroscopy allowed structure-activity relationship assignments to be made for a variety of intermediates occurring during the post-PKS tailoring sequence in ansamitocin biosynthesis.