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Blood ; 134(2): 147-159, 2019 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-31015190


Hemophagocytic lymphohistiocytosis (HLH) is an often-fatal disorder characterized by the overactivation of T cells and macrophages that excessively produce proinflammatory cytokines, including interferon-γ (IFN-γ). Previously, we reported that the JAK inhibitor ruxolitinib dampens T-cell activation and lessens inflammation in a model of HLH in which perforin-deficient (Prf1 -/-) mice are infected with lymphocytic choriomeningitis virus (LCMV). Ruxolitinib inhibits signaling downstream of IFN-γ, as well as several other JAK-dependent cytokines. As a consequence, it remained unclear whether ruxolitinib was exerting its beneficial effects in HLH by inhibiting IFN-γ signaling or by targeting signaling initiated by other proinflammatory cytokines. To address this question, we compared the effects of ruxolitinib with those obtained using an IFN-γ-neutralizing antibody (αIFN-γ) in 2 murine HLH models. In both models, ruxolitinib and αIFN-γ reduced inflammation-associated anemia, indicating that ruxolitinib operates in an IFN-γ-dependent manner to reverse this HLH manifestation. In contrast, the number and activation status of T cells and neutrophils, as well as their infiltration into tissues, were significantly reduced following treatment with ruxolitinib, but they remained unchanged or were increased following treatment with αIFN-γ. Notably, despite discontinuation of ruxolitinib, LCMV-infected Prf1 -/- mice exhibited enhanced survival compared with mice in which αIFN-γ was discontinued. This protective effect could be mimicked by transient treatment with αIFN-γ and a neutrophil-depleting antibody. Thus, ruxolitinib operates through IFN-γ-dependent and -independent mechanisms to dampen HLH by targeting the deleterious effects of T cells and neutrophils, with the latter representing an unappreciated and understudied cell type that contributes to HLH pathogenesis.

Linfo-Histiocitose Hemofagocítica/imunologia , Neutrófilos/efeitos dos fármacos , Pirazóis/farmacologia , Linfócitos T/efeitos dos fármacos , Animais , Modelos Animais de Doenças , Ativação Linfocitária/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL
Cancer Cell ; 33(5): 937-948.e8, 2018 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-29681510


Somatic genetic alterations of IKZF1, which encodes the lymphoid transcription factor IKAROS, are common in high-risk B-progenitor acute lymphoblastic leukemia (ALL) and are associated with poor prognosis. Such alterations result in the acquisition of stem cell-like features, overexpression of adhesion molecules causing aberrant cell-cell and cell-stroma interaction, and decreased sensitivity to tyrosine kinase inhibitors. Here we report coding germline IKZF1 variation in familial childhood ALL and 0.9% of presumed sporadic B-ALL, identifying 28 unique variants in 45 children. The majority of variants adversely affected IKZF1 function and drug responsiveness of leukemic cells. These results identify IKZF1 as a leukemia predisposition gene, and emphasize the importance of germline genetic variation in the development of both familial and sporadic ALL.

Mutação em Linhagem Germinativa , Fator de Transcrição Ikaros/genética , Fator de Transcrição Ikaros/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Animais , Criança , Feminino , Mutação da Fase de Leitura , Predisposição Genética para Doença , Humanos , Masculino , Camundongos , Transplante de Neoplasias , Linhagem , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , Análise de Sequência de DNA
Blood ; 127(13): 1666-75, 2016 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-26825707


Hemophagocytic lymphohistiocytosis (HLH) comprises an emerging spectrum of inherited and noninherited disorders of the immune system characterized by the excessive production of cytokines, including interferon-γ and interleukins 2, 6, and 10 (IL-2, IL-6, and IL-10). The Janus kinases (JAKs) transduce signals initiated following engagement of specific receptors that bind a broad array of cytokines, including those overproduced in HLH. Based on the central role for cytokines in the pathogenesis of HLH, we sought to examine whether the inhibition of JAK function might lessen inflammation in murine models of the disease. Toward this end, we examined the effects of JAK inhibition using a model of primary (inherited) HLH in which perforin-deficient (Prf1(-∕-)) mice are infected with lymphocytic choriomeningitis virus (LCMV) and secondary (noninherited) HLH in which C57BL/6 mice receive repeated injections of CpG DNA. In both models, treatment with the JAK1/2 inhibitor ruxolitinib significantly lessened the clinical and laboratory manifestations of HLH, including weight loss, organomegaly, anemia, thrombocytopenia, hypercytokinemia, and tissue inflammation. Importantly, ruxolitinib treatment also significantly improved the survival of LCMV-infectedPrf1(-∕-)mice. Mechanistic studies revealed that in vivo exposure to ruxolitinib inhibited signal transducer and activation of transcription 1-dependent gene expression, limited CD8(+)T-cell expansion, and greatly reduced proinflammatory cytokine production, without effecting degranulation and cytotoxic function. Collectively, these findings highlight the JAKs as novel, druggable targets for mitigating the cytokine-driven hyperinflammation that occurs in HLH. These observations also support the incorporation of JAK inhibitors such as ruxolitinib into future clinical trials for patients with these life-threatening disorders.

Inflamação/prevenção & controle , Janus Quinases/antagonistas & inibidores , Ativação Linfocitária/efeitos dos fármacos , Linfo-Histiocitose Hemofagocítica/genética , Linfo-Histiocitose Hemofagocítica/patologia , Pirazóis/farmacologia , Animais , Células Cultivadas , Ilhas de CpG , Modelos Animais de Doenças , Linfo-Histiocitose Hemofagocítica/tratamento farmacológico , Linfo-Histiocitose Hemofagocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Perforina/genética , Pirazóis/uso terapêutico , Células Vero
Sci Transl Med ; 8(321): 321ra7, 2016 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-26764158


X-linked lymphoproliferative disease (XLP-1) is an often-fatal primary immunodeficiency associated with the exuberant expansion of activated CD8(+) T cells after Epstein-Barr virus (EBV) infection. XLP-1 is caused by defects in signaling lymphocytic activation molecule (SLAM)-associated protein (SAP), an adaptor protein that modulates T cell receptor (TCR)-induced signaling. SAP-deficient T cells exhibit impaired TCR restimulation-induced cell death (RICD) and diminished TCR-induced inhibition of diacylglycerol kinase α (DGKα), leading to increased diacylglycerol metabolism and decreased signaling through Ras and PKCθ (protein kinase Cθ). We show that down-regulation of DGKα activity in SAP-deficient T cells restores diacylglycerol signaling at the immune synapse and rescues RICD via induction of the proapoptotic proteins NUR77 and NOR1. Pharmacological inhibition of DGKα prevents the excessive CD8(+) T cell expansion and interferon-γ production that occur in SAP-deficient mice after lymphocytic choriomeningitis virus infection without impairing lytic activity. Collectively, these data highlight DGKα as a viable therapeutic target to reverse the life-threatening EBV-associated immunopathology that occurs in XLP-1 patients.

Diacilglicerol Quinase/antagonistas & inibidores , Transtornos Linfoproliferativos/imunologia , Transtornos Linfoproliferativos/patologia , Animais , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/metabolismo , Morte Celular/efeitos dos fármacos , Citocinas/biossíntese , Diacilglicerol Quinase/metabolismo , Inativação Gênica/efeitos dos fármacos , Humanos , Sinapses Imunológicas/efeitos dos fármacos , Sinapses Imunológicas/metabolismo , Ativação Linfocitária , Contagem de Linfócitos , Transtornos Linfoproliferativos/tratamento farmacológico , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Proteína Quinase C/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Pirimidinonas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária/deficiência , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária/metabolismo , Tiazóis/farmacologia , Proteínas ras/metabolismo