title: Selective blockade of lymphopoiesis induced by kalanchosine dimalate: inhibition of IL-7-dependent proliferation.
abstract: Lymphopoiesis and myelopoiesis continuously generate mature cells from hematopoietic cell progenitors during the lifetime of the organism. The identification of new endogenous or exogenous substances that can act specifically on the differentiation of distinct cell lineages is of relevance and has potential therapeutical use. Kalanchoe brasiliensis (Kb) is a medicinal plant from the Crassulaceae family, used in folk medicine to treat inflammatory and infectious diseases. Here, we show that short-term treatment of naïve mice with Kb led to a strong and selective inhibition of lymphopoiesis, affecting B and T cell lineages without reduction of the myeloid lineage development. Similar effects were observed after treatment with the highly purified compound kalanchosine dimalate (KMC), obtained from Kb. Numbers of mature lymphocytes in secondary lymphoid organs were preserved in Kb(KMC)-treated mice. The effect of Kb(KMC) was not a result of secondary augmentation of plasma levels of endogenous corticoids; neither involves TNF-alpha, type-I IFN, or TLR2/TLR4 ligands, which have all been described as selective inhibitors of lymphopoiesis. Flow cytometry analysis of the phenotypes of T and B cell precursors indicate a blockade of maturation on IL-7-dependent, proliferative stages. In vitro, Kb(KMC) inhibited the IL-7-dependent proliferation of pre-B cells and does not induce massive apoptosis of B and T cell precursors. These results suggest that Kb(KMC) is selectively blocking lymphopoiesis through a mechanism that does not involve the previously characterized substances, possibly acting on the IL-7 signaling pathway, opening new perspectives for a potential therapeutic use of Kb-derived drugs.
authors.affiliation: Departamento de Imunologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, CCS, Bl.I, sala I2-051, Cidade Universitária, CEP:21941-902, Rio de Janeiro, Brazil.
authors.forename: Luciana S
authors.initials: LS
authors.lastname: de Paiva
authors.forename: Alberto
authors.initials: A
authors.lastname: Nobrega
authors.forename: Giany O
authors.initials: GO
authors.lastname: De Melo
authors.forename: Elize A
authors.initials: EA
authors.lastname: Hayashi
authors.forename: Vinicius
authors.initials: V
authors.lastname: Carvalho
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Rodrigues E Silva
authors.forename: Maria
authors.initials: M
authors.lastname: Bellio
authors.forename: Gerlinde P
authors.initials: GP
authors.lastname: Teixeira
authors.forename: Vivian
authors.initials: V
authors.lastname: Rumjanek
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Costa
authors.forename: Vera Lúcia G
authors.initials: VL
authors.lastname: Koatz
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D015851:Interleukin-7 / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D031962:Kalanchoe; D038041:Lymphopoiesis / Q000187:drug effects / Q000502:physiology*; D008293:Malates / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D023421:Models, Animal; D010936:Plant Extracts; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000172:deficiency / Q000235:genetics; D051195:Toll-Like Receptor 2 / Q000172:deficiency / Q000235:genetics
chemical_list: D000893:Anti-Inflammatory Agents; D015851:Interleukin-7; D008293:Malates; D010936:Plant Extracts; D047888:Receptors, Tumor Necrosis Factor, Type I; C493486:Tlr2 protein, mouse; C506236:Tnfrsf1a protein, mouse; D051195:Toll-Like Receptor 2; C511573:kalanchosine dimalate