RESUMO
Notch signaling governs crucial aspects of intercellular communication spanning antigen-presenting cells and T-cells. In this study, we investigate how Leishmaniadonovani takes advantage of this pathway to quell host immune responses. We report induction of the Notch ligand Jagged1 in L. donovani-infected bone marrow macrophages (BMMÏs) and subsequent activation of RBPJκ (also known as RBPJ) in T cells, which in turn upregulates the transcription factor GATA3. Activated RBPJκ also associates with the histone acetyltransferase p300 (also known as EP300), which binds with the Bcl2l12 promoter and enhances its expression. Interaction of Bcl2L12 with GATA3 in CD4+ T cells facilitates its binding to the interleukin (IL)-10 and IL-4 promoters, thereby increasing the secretion of these cytokines. Silencing Jagged1 hindered these events in a BMMÏ-T cell co-culture system. Upon further scrutiny, we found that parasite lipophosphoglycan (LPG) induces the host phosphoinositide 3-kinase (PI3K)/Akt pathway, which activates ß-catenin and Egr1, the two transcription factors responsible for driving Jagged1 expression. In vivo morpholino-silencing of Jagged1 suppresses anti-inflammatory cytokine responses and reduces organ parasite burden in L. donovani-infected Balb/c mice, suggesting that L. donovani-induced host Jagged1-Notch signaling skews macrophage-T cell crosstalk into disease-promoting Th2 mode in experimental visceral leishmaniasis.This article has an associated First Person interview with the first author of the paper.
Assuntos
Leishmania donovani , Leishmaniose Visceral , Animais , Anti-Inflamatórios , Camundongos , Camundongos Endogâmicos BALB C , Fosfatidilinositol 3-QuinasesRESUMO
Reciprocal changes in histone lysine methylation/demethylation of M(LPS + IFN-γ)/M(IL-10) genes is one of the factors that direct macrophage polarization and contribute to host defense/susceptibility toward infection. Although, histone lysine methyltransferases and lysine demethylases orchestrate these events, their role remains elusive in visceral leishmaniasis, a disease associated with macrophage M(IL-10) polarization. In this study, we observed that L. donovani induced the expression of histone lysine methyltransferases Ash1l, Smyd2, and Ezh2 and histone lysine demethylases Kdm5b and Kdm6b in J774 macrophages and BALB/c mice. Chromatin immunoprecipitation analysis revealed that L. donovani facilitated H3K36 dimethylation at TNF-α promoter by Smyd2 and H3K27 trimethylation at inducible NO synthase promoter by Ezh2 to suppress their expression in macrophages. Furthermore, infection-induced Kdm5b and Kdm6b modulated H3K4 and H3K27 trimethylation at IL-12, TNF-α, and arginase-1 promoters, respectively, whereas H3K4 trimethylation by Ash1l at IL-10 promoter induced its expression. Analysis of transductional events revealed that HIF-1α upregulated Kdm5b and Kdm6b expression, whereas Ash1l and Ezh2 expression were induced by transcription factor MeCP2. Additionally, Smyd2 was induced by c-Myc in infected macrophages. Knockdown of Ash1l, Ezh2, Kdm5b, and Kdm6b by specific small interfering RNA and Vivo-Morpholino, as well as inhibition of Smyd2 by its specific inhibitor, AZ505, led to increased protective proinflammatory response and inhibited amastigote multiplication in infected J774 macrophages and BALB/c mice, respectively. Collectively, our findings demonstrate that L. donovani exploits specific histone lysine methyltransferases/demethylases to redirect epigenetic programming of M(LPS + IFN-γ)/M(IL-10) genes for its successful establishment within the host.
Assuntos
Interferon gama/metabolismo , Interleucina-10/metabolismo , Leishmania donovani/fisiologia , Leishmaniose Visceral/imunologia , Macrófagos/imunologia , Animais , Diferenciação Celular , Linhagem Celular , Reprogramação Celular , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Epigênese Genética , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Evasão da Resposta Imune , Lipopolissacarídeos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , RNA Interferente Pequeno/genéticaRESUMO
Immune evasion strategies adopted by Leishmania donovani involve the exploitation of suppressor of cytokine signaling (SOCS) proteins that are well-known negative regulators of the JAK/STAT pathway. However, the cellular mechanism underpinning the induction of SOCS isoforms and their role in breaching the multilevel regulatory circuit connecting the innate and adaptive arms of immunity are still ambiguous during experimental visceral leishmaniasis. Using bone marrow-derived macrophages (BMMÑs) and CD4+ T cells, we observed that L. donovani preferentially upregulates SOCS1 and SOCS3 expression in macrophages and T cells, respectively, whereas the SOCS1 level remains consistently high in BMMÑs and SOCS3 expression is pronounced and long lasting in T cells. Consequently, this inhibits STAT1-mediated IL-12 induction in macrophages & STAT4-mediated IFN-γ synthesis in T cells. Mechanistically, PI3K/Akt-mediated SRF activation promotes nuclear translocation and binding of Egr2 to SOCS1 promoter for its early induction in infected BMMÑs. Additionally, L. donovani activates IDO/kynurenine/AHR signaling in BMMÑs to maintain prolonged SOCS1 expression. Later, PGE2, secreted from infected BMMÑs induces cAMP-PKA pathway by binding to the EP2/EP4 receptor of CD4+ T cells, leading to SP1, CREB, and GATA1 activation and SOCS3 expression. Small interfering RNA-mediated silencing of SOCS1 and SOCS3 in macrophage and T cells, respectively, restored IL-12 and IFN-γ cytokine levels and BMMÑ-T cell interaction. Vivo morpholino-mediated silencing of SOCS1 and SOCS3 resulted in protective cytokine responses, thereby reducing organ parasite burden significantly in L. donovani-infected BALB/c mice. Collectively, our results imply that L. donovani orchestrates different SOCS isoforms to impair macrophage-T cell cross-talk and preserve its own niche.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Leishmania donovani/fisiologia , Leishmaniose Visceral/imunologia , Macrófagos/imunologia , Proteína 1 Supressora da Sinalização de Citocina/metabolismo , Proteína 3 Supressora da Sinalização de Citocinas/metabolismo , Animais , Comunicação Celular , Células Cultivadas , Modelos Animais de Doenças , Humanos , Evasão da Resposta Imune , Imunidade Celular , Interferon gama/metabolismo , Interleucina-12/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Isoformas de Proteínas/genética , RNA Interferente Pequeno/genética , Transdução de Sinais , Proteína 1 Supressora da Sinalização de Citocina/genética , Proteína 3 Supressora da Sinalização de Citocinas/genética , Regulação para CimaRESUMO
IL-1R/TLR signaling plays a significant role in sensing harmful foreign pathogens and mounting effective innate and adaptive immune responses. However, the precise mechanism by which Leishmania donovani, an obligate intramacrophagic pathogen, breaches IL-1R/TLR signaling and host-protective immunity remains obscure. In this study, we report the novel biphasic role of Toll-interacting protein (Tollip), a negative regulator of the IL-1R/TLR pathway, in the disease progression of experimental visceral leishmaniasis. We observed that during early hours of infection, L. donovani induced phosphorylation of IRAK-1, resulting in the release of Tollip from the IL-1R-associated kinase (IRAK)-1 complex in J774 macrophages, which then acted as an endocytic adaptor on cell surface IL-1R1 and promoted its lysosomal degradation. In the later stage, Tollip shuttled back to IRAK-1, thereby inhibiting IRAK-1 phosphorylation in association with IRAK-M to neutralize downstream TLR signaling in infected macrophages. Moreover, during late infection, L. donovani enhanced nuclear translocation and recruitment of transcription factors early growth response protein 2, NF erythroid 2-related factor 2, and Ahr on Tollip promoter for its induction. Small interfering RNA-mediated silencing of Tollip in infected macrophages significantly enhanced NF-κB activation and induced host-defensive IL-12 and TNF-α synthesis, thereby reducing amastigote multiplication. Likewise, abrogation of Tollip in L. donovani-infected BALB/c mice resulted in STAT-1-, IRF-1-, and NF-κB-mediated upregulation of host-protective cytokines and reduced organ parasite burden, thereby implicating its role in disease aggravation. Taken together, we conclude that L. donovani exploited the multitasking function of Tollip for its own establishment through downregulating IL-1R1/TLR signaling in macrophages.
Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/imunologia , Leishmania donovani/imunologia , Receptores de Interleucina-1/imunologia , Transdução de Sinais/imunologia , Receptores Toll-Like/imunologia , Animais , Células Cultivadas , Regulação para Baixo/imunologia , Feminino , Quinases Associadas a Receptores de Interleucina-1/imunologia , Leishmaniose Visceral/imunologia , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , NF-kappa B , Fosforilação/imunologia , Fator de Transcrição STAT1/imunologia , Fator de Necrose Tumoral alfa/imunologia , Regulação para Cima/imunologiaRESUMO
In an endeavor to search for affordable and safer therapeutics against debilitating visceral leishmaniasis, we examined antileishmanial potential of ammonium trichloro [1,2-ethanediolato-O,O']-tellurate (AS101); a tellurium based non toxic immunomodulator. AS101 showed significant in vitro efficacy against both Leishmania donovani promastigotes and amastigotes at sub-micromolar concentrations. AS101 could also completely eliminate organ parasite load from L. donovani infected Balb/c mice along with significant efficacy against infected hamsters (Ë93% inhibition). Analyzing mechanistic details revealed that the double edged AS101 could directly induce apoptosis in promastigotes along with indirectly activating host by reversing T-cell anergy to protective Th1 mode, increased ROS generation and anti-leishmanial IgG production. AS101 could inhibit IL-10/STAT3 pathway in L. donovani infected macrophages via blocking α4ß7 integrin dependent PI3K/Akt signaling and activate host MAPKs and NF-κB for Th1 response. In silico docking and biochemical assays revealed AS101's affinity to form thiol bond with cysteine residues of trypanothione reductase in Leishmania promastigotes leading to its inactivation and inducing ROS-mediated apoptosis of the parasite via increased Ca2+ level, loss of ATP and mitochondrial membrane potential along with metacaspase activation. Our findings provide the first evidence for the mechanism of action of AS101 with excellent safety profile and suggest its promising therapeutic potential against experimental visceral leishmaniasis.
Assuntos
Etilenos/uso terapêutico , Integrinas/antagonistas & inibidores , Leishmania donovani/enzimologia , Leishmaniose Visceral/tratamento farmacológico , NADH NADPH Oxirredutases/efeitos dos fármacos , Animais , Células Cultivadas , Cricetinae , Modelos Animais de Doenças , Etilenos/farmacologia , Feminino , Interações Hospedeiro-Parasita/efeitos dos fármacos , Integrinas/efeitos dos fármacos , Leishmania donovani/efeitos dos fármacos , Leishmania donovani/metabolismo , Leishmaniose Visceral/metabolismo , Leishmaniose Visceral/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , NADH NADPH Oxirredutases/metabolismo , Oxirredução/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/efeitos dos fármacos , Inibidores de Fosfoinositídeo-3 Quinase , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacosRESUMO
Follicular helper T (Tfh) cells have been implicated in controlling rejection after allogeneic kidney transplantation, but the precise subsets, origins, and functions of Tfh cells in this process have not been fully characterized. Here we show that a subset of effector Tfh cells marked by previous IL-21 production is potently induced during allogeneic kidney transplantation and is inhibited by immunosuppressive agents. Single-cell RNA-Seq revealed that these lymph node (LN) effector Tfh cells have transcriptional and clonal overlap with IL-21-producing kidney-infiltrating Tfh cells, implicating common origins and developmental trajectories. To investigate the precise functions of IL-21-producing effector Tfh cells in LNs and allografts, we used a mouse model to selectively eliminate these cells and assessed allogeneic B cell clonal dynamics using a single B cell culture system. We found that IL-21-producing effector Tfh cells were essential for transplant rejection by regulating donor-specific germinal center B cell clonal dynamics both systemically in the draining LN and locally within kidney grafts. Thus, IL-21-producing effector Tfh cells have multifaceted roles in Ab-mediated rejection after kidney transplantation by promoting B cell alloimmunity.
Assuntos
Células T Auxiliares Foliculares , Linfócitos T Auxiliares-Indutores , Camundongos , Animais , Linfonodos , Rim , AloenxertosRESUMO
Follicular helper T (Tfh) cells are essential for the formation of high affinity antibodies after vaccination or infection. Although the signals responsible for initiating Tfh differentiation from naïve T cells have been studied, the signals controlling sequential developmental stages culminating in optimal effector function are not well understood. Here we use fate mapping strategies for the cytokine IL-21 to uncover sequential developmental stages of Tfh differentiation including a progenitor-like stage, a fully developed effector stage and a post-effector Tfh stage that maintains transcriptional and epigenetic features without IL-21 production. We find that progression through these stages are controlled intrinsically by the transcription factor FoxP1 and extrinsically by follicular regulatory T cells. Through selective deletion of Tfh stages, we show that these cells control antibody dynamics during distinct stages of the germinal center reaction in response to a SARS-CoV-2 vaccine. Together, these studies demonstrate the sequential phases of Tfh development and how they promote humoral immunity.
Assuntos
Células T Auxiliares Foliculares , Linfócitos T Auxiliares-Indutores , Humanos , Vacinas contra COVID-19 , Imunidade Humoral , Centro Germinativo , Diferenciação Celular , Fatores de TranscriçãoRESUMO
Unmethylated CpG motifs with phosphothioate backbone trigger TLR9 to elicit innate immune response characterized by the production of Th1 cytokines. The use of CpG DNA as an adjuvant has established its role in potentiating the humoral and cell mediated vaccine specific immune response. However, none of the synthetic oligodeoxynucleotides (ODNs) know and used till date are associated with the parasite itself. Our group identified a novel CG rich sequence of 14 base pairs from Leishmania donovani genome (Ld CpG ODN) and established it as a TLR9 agonist. The present study was designed to ascertain the adjuvanticity of Ld CpG ODN with soluble leishmanial antigen in experimental model of L. donovani. During the study Schizophyllan (SPG), a fungal polymer was used for encapsulating Ld CpG ODN for efficient endosomal delivery. The synthesized nanovehicles were of nearly 100 nm and localized within endosomes as confirmed by confocal microscopy. Immunization studies displayed the superior ability of synthesized nanovehicles co-administered with parasite antigen in augmenting innate immune response in comparison to ODN, nanoparticles or soluble antigen alone. The response included generation of ROS, NO and iNOS expression followed by proinflammatory cytokine milieu with reduced parasitic load within liver, spleen and bone marrow. These immune-tailored particles in combination with parasitic antigens elicited significant generation of cell mediated response owing to the presence of high levels of CD8+ T-cells and lymphocyte proliferation. Moreover, vaccination regime with synthesized adjuvant also activated humoral immunity by escalating the levels of IgG2 followed by reduced levels of anti-leishmanial IgG and IgG1 antibodies. The findings support the efficacy of Ld CpG ODN as a potential adjuvant against visceral leishmaniasis.
Assuntos
Adjuvantes Imunológicos/administração & dosagem , Antígenos de Protozoários/administração & dosagem , Leishmania donovani/imunologia , Leishmaniose Visceral/prevenção & controle , Nanopartículas , Oligodesoxirribonucleotídeos/administração & dosagem , Vacinas Protozoárias/administração & dosagem , Sizofirano/administração & dosagem , Adjuvantes Imunológicos/química , Animais , Antígenos de Protozoários/química , Modelos Animais de Doenças , Composição de Medicamentos , Interações Hospedeiro-Patógeno , Imunidade Celular/efeitos dos fármacos , Imunidade Humoral/efeitos dos fármacos , Imunogenicidade da Vacina , Leishmania donovani/patogenicidade , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Masculino , Mesocricetus , Oligodesoxirribonucleotídeos/química , Vacinas Protozoárias/química , Sizofirano/química , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/metabolismo , Linfócitos T/parasitologia , Receptor Toll-Like 9/agonistas , Receptor Toll-Like 9/metabolismo , VacinaçãoRESUMO
The current therapeutic regimen for visceral leishmaniasis is inadequate and unsatisfactory due to toxic side effects, high cost and emergence of drug resistance. Alternative, safe and affordable antileishmanials are, therefore, urgently needed and toward these we synthesized a series of arylpiperazine substituted pyranone derivatives and screened them against both in vitro and in vivo model of visceral leishmaniasis. Among 22 synthesized compounds, 5a and 5g showed better activity against intracellular amastigotes with an IC50 of 11.07 µM and 15.3 µM, respectively. In the in vivo, 5a significantly reduced hepatic and splenic amastigotes burden in Balb/c mice model of visceral leishmaniasis. On a mechanistic node, we observed that 5a induced direct Leishmania killing via mitochondrial dysfunction like cytochrome c release and loss of membrane potential. Taken together, our results suggest that 5a is a promising lead for further development of antileishmanial drugs.
Assuntos
Antiprotozoários/farmacologia , Desenho de Fármacos , Leishmania donovani/efeitos dos fármacos , Piperazina/farmacologia , Piridonas/farmacologia , Animais , Antiprotozoários/síntese química , Antiprotozoários/química , Células Cultivadas , Relação Dose-Resposta a Droga , Camundongos , Estrutura Molecular , Testes de Sensibilidade Parasitária , Piperazina/química , Piridonas/química , Relação Estrutura-AtividadeRESUMO
CD11c+CD8α+ and CD11c+CD11b+ dendritic cells are two major subsets of murine splenic CD11c+ DCs which play a crucial role in T cell priming and shaping Th1/Th2 responses, but their role in the context of experimental visceral leishmaniasis (VL) is poorly understood. Herein, we showed that L. donovani infection in Balb/c mice preferentially decreased the population abundance of CD11c+CD11b+ DCs and increased relative abundance of splenic CD11c+CD8α +DCs. During infection, splenic CD11c+CD11b+ DCs induced Th1 differentiation whereas CD11c+CD8α+ DCs promoted Th2 differentiation. Additionally, treatment of infected mice with miltefosine as experimental control exhibited host defense allowing the restoration of CD11c+CD11b+ population and decrease in CD11c+CD8α+ subset. Furthermore, reciprocal regulation of immune accessory surface molecules, Sema4A and OX40L critically determined Th1/Th2 response induced by these DC subsets during VL. L. donovani infection significantly induced OX40L expression and slightly downregulated SEMA 4A expression in CD11c+CD8α+ DCs whereas miltefosine treatment significantly downregulated OX40L expression along with pronounced upregulation of SEMA 4A expression in CD11c+CD11b+ DCs. SiRNA mediated knockdown of SEMA 4A markedly reduced CD11c+CD11b+ driven IFN-γ, TNF-α and IL-12 synthesis in miltefosine treated mice whereas functional blocking of OX40L decreased CD11c+CD8α+ induced IL-10, IL-4 and TGF-ß synthesis in L. donovani infected group. Vaccination of Balb/c mice with antigen-pulsedâ¯+â¯CpG-ODN-activated DC subsets revealed that only antigen-pulsed CD11c+CD11b+ DCs eliminated parasite load in visceral organ and restored protective Th1 cytokine response. Collectively, our results suggest that differential regulation of splenic CD11c+ subsets by L. donovani is essential for disease progression and specific subtypes may be exploited as prophylactic measures against visceral leishmaniasis.
Assuntos
Citocinas/imunologia , Células Dendríticas/imunologia , Leishmaniose Visceral/imunologia , Baço/imunologia , Animais , Antígeno CD11b/imunologia , Antígeno CD11c/imunologia , Antígenos CD8/imunologia , Diferenciação Celular/imunologia , Modelos Animais de Doenças , Progressão da Doença , Feminino , Imunidade , Camundongos , Camundongos Endogâmicos BALB CRESUMO
ß-amino acids and their analogues are gathering increased attention not only because of their antibacterial and antifungal activity, but also for their use in designing peptidomimetics with increased oral bioavailability and resistance to metabolic degradation. In this study, a series of α-phenyl substituted chalcones, α-phenyl, ß-amino substituted dihydrochalcones and ß-amino acid derivatives were synthesized and evaluated for their antileishmanial efficacy against experimental visceral leishmaniasis (VL). Among all synthesized derivatives, 10c showed promising antileishmanial efficacy against both extracellular promastigote and intracellular amastigote (IC50 8.2⯵M and 20.5⯵M respectively) of L. donovani with negligible cytotoxic effect towards J774 macrophages and Vero cells. 10c effectively reduced spleen and liver parasite burden (>90%) in both hamster and Balb/c model of VL without any hepatotoxicity. In vitro pharmacokinetic analysis showed that 10c was stable in gastric fluid and plasma of Balb/c mice at 10⯵g/ml. Further analysis of the molecular mechanism revealed that 10c entered into the parasite by depolarizing the plasma membrane rather than forming nonspecific pores and induced molecular events like loss in mitochondrial membrane potential with a gradual decline in ATP production. This, in turn, did not induce programmed cell death of the parasite; rather 10c induced bioenergetic collapse of the parasite by decreasing ATP synthesis through specific inhibition of mitochondrial complex III activity. Altogether, our results allude to the therapeutic potential of ß-amino acid derivatives as novel antileishmanials, identifying them as lead compounds for further exploration in the design of potent candidates for the treatment of visceral leishmaniasis.
Assuntos
Aminoácidos/farmacologia , Antiprotozoários/farmacologia , Complexo III da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Leishmania donovani/efeitos dos fármacos , Leishmaniose Visceral/tratamento farmacológico , Mitocôndrias/efeitos dos fármacos , Aminoácidos/química , Animais , Antiprotozoários/química , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops , Cricetinae , Relação Dose-Resposta a Droga , Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Leishmania donovani/metabolismo , Leishmaniose Visceral/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Mitocôndrias/metabolismo , Estrutura Molecular , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade , Células VeroRESUMO
In our efforts to identify novel chemical scaffolds for the development of antileishmanial agents, a series of quinoline-metronidazole hybrid compounds was synthesized and tested against the murine model of visceral leishmaniasis. Among all synthesized derivatives, 15b and 15i showed significant antileishmanial efficacy against both extracellular promastigote (IC50 9.54 and 5.42 µM, respectively) and intracellular amastigote (IC50 9.81 and 3.75 µM, respectively) forms of Leishmania donovani with negligible cytotoxicity toward the host (J774 macrophages, Vero cells). However, compound 15i effectively inhibited the parasite burden in the liver and spleen (>80%) of infected BALB/c mice. Mechanistic studies revealed that 15i triggers oxidative stress which induces bioenergetic collapse and apoptosis of the parasite by decreasing ATP production and mitochondrial membrane potential. Structure-activity analyses and pharmacokinetic studies suggest 15i as a promising antileishmanial lead and emphasize the importance of quinoline-metronidazole series as a suitable platform for the future development of antileishmanial agents.
Assuntos
Antiprotozoários/síntese química , Antiprotozoários/farmacologia , Leishmaniose Visceral/tratamento farmacológico , Metronidazol/síntese química , Metronidazol/farmacologia , Quinolinas/química , Animais , Antiprotozoários/química , Antiprotozoários/farmacocinética , Técnicas de Química Sintética , Chlorocebus aethiops , Modelos Animais de Doenças , Leishmania donovani/efeitos dos fármacos , Leishmania donovani/fisiologia , Metronidazol/química , Metronidazol/farmacocinética , Ratos , Relação Estrutura-Atividade , Distribuição Tecidual , Células VeroRESUMO
UNLABELLED: 15-Deoxy-delta (12,14)-prostaglandin J2 (15d-PgJ2) is a potent bioactive lipid mediator, known to possess several roles in cell regulation and differentiation along with antimicrobial efficacy against different bacterial and viral infections. In the present study, we investigated the therapeutic efficacy and mechanism of action of 15d-PgJ2 in vitro in Leishmania donovani promastigotes and infected J774 macrophages, and in vivo in Balb/c mice/golden hamster model of experimental visceral leishmaniasis. 15d-PgJ2 effectively killed L. donovani promastigotes and amastigotes in vitro with IC50 of 104.6 and 80.09 nM, respectively. At 2 mg/kg (mice) and 4 mg/kg (hamster) doses, 15d-PgJ2 decreased >90 % spleen and liver parasite burden. It significantly reduced interleukin (IL)-10 and transforming growth factor (TGF)-ß synthesis in infected macrophages and splenocytes. 15d-PgJ2 induced reactive oxygen species (ROS)-dependent apoptosis of promastigotes by triggering phosphatidyl serine externalization, mitochondrial membrane damage and inducing caspase-like activity. In vitro drug interaction studies revealed an indifference to the synergistic association of 15d-PgJ2 with Miltefosine and Amphotericin-B (Amp-B). Moreover, when combined with sub-curative doses of Miltefosine and Amphotericin-B, 15d-PgJ2 resulted in >95 % parasite removal. Our results suggested that 15d-PgJ2 induces mitochondria-dependent apoptosis of L. donovani and is a good therapeutic candidate for adjunct therapy against experimental visceral leishmaniasis. KEY MESSAGE: 15d-PgJ2 effectively eliminated both promastigotes and amastigotes form of L. donovani. 15d-PgJ2 decreased parasite burden from infected mice and hamsters with reduced Th2 cytokines. 15d-PgJ2 induced ROS-mediated mitochondrial apoptosis of L. donovani promastigotes. 15d-PgJ2 is a good therapeutic candidate for adjunct therapy with Miltefosine and Amp-B.