Unwinding the mechanism of macrophage repolarization potential of Oceanimonas sp. BPMS22-derived protein protease inhibitor through Toll-like receptor 4 against experimental visceral leishmaniasis.

The Oceanimonas sp. BPMS22-derived protein protease inhibitor (PPI) has been proven to shift macrophages towards an inflammatory state and reduce Leishmania donovani infection in vitro and in vivo. The current study explored and validated the mechanistic aspects of the PPI and Toll-like receptor (TLR) interaction. The PPI exhibited the upregulation of TLR2, TLR4, and TLR6 during treatment which was proven to orchestrate parasite clearance effectively. An in silico study confirmed the high interaction with TLR4 and PPI. Immune blotting confirmed the significant upregulation of TLR4 in macrophages irrespective of L. donovani infection. Pharmacological inhibition and immune blot study confirmed the involvement of the PPI in TLR4-mediated phosphorylation of p38 MAPK and dephosphorylation of ERK1/2, repolarizing to pro-inflammatory macrophage state against experimental visceral leishmaniasis. In addition, in TLR4 knockdown condition, PPI treatment failed to diminish M2 phenotypical markers (CD68, Fizz1, Ym1, CD206, and MSR-2) and anti-inflammatory cytokines (IL-4, IL-10, and TGF-ß). Simultaneously, the PPI failed to upregulate the M1 phenotypical markers and pro-inflammatory cytokines (IL-1ß, IL-6, IL-12, and IFN-γ) (p < 0.001) during the TLR4 knockdown condition. In the absence of TLR4, the PPI also failed to reduce the parasite load and T-cell proliferation and impaired the delayed-type hypersensitivity response. The absence of pro-inflammatory cytokines was observed during a co-culture study with PPI-treated macrophages (in the TLR4 knockdown condition) with day 10 T-cell obtained from L. donovani-infected mice. This study supports the immunotherapeutic potential of the PPI as it interacted with TLR4 and promoted macrophage repolarization (M2-M1) to restrict the L. donovani parasite burden and helps in the mounting immune response against experimental visceral leishmaniasis.

Partial characterization of purified glycoprotein from nutshell of Arachis hypogea L. towards macrophage activation and leishmaniacidal activity.

Arachis hypogea L. protein fraction-2 (AHP-F2) from the Peanut shell was extracted and characterized and its potent immunomodulatory and anti-leishmanial role was determined in this present study. AHP-F2 was found to be a glycoprotein as the presence of carbohydrates were confirmed by the analysis of high-performance liquid chromatography (HPLC) yielded glucose, galactose, mannose, and xylose. AHP-F2 molecular mass was found to be ∼28 kDa as indicated in MALDI-TOF and peptide mass fingerprinting analysis followed by Mascot search. The peptide matches revealed the similarity of the mannose/glucose binding lectin with 71.07% in the BLAST analysis. After that, the 3D structure of the AHP-F2 model was designed and validated by the Ramachandran plot. The immunomodulatory role of AHP-F2 was established in murine peritoneal macrophages as induction of nitric oxide (NO), and stimulation of proinflammatory cytokines (IL-12 and IFN-γ) in a dose-dependent manner was observed. Interestingly, it was also found that AHP-F2 has interacted with the innate immune receptor, toll-like receptors (TLRs) as established in molecular docking as well as mRNA expression. The anti-leishmanial potential of AHP-F2 was revealed with a prominent inhibition of amastigote growth within the murine macrophages with prompt induction of nitrite release. Altogether, the isolated AHP-F2 from Arachis hypogea L. has strong immunomodulatory and anti-leishmanial potential which may disclose a new path to treat leishmaniasis.

Oceanimonas sp. BPMS22-derived protein protease inhibitor induces anti-leishmanial immune responses through macrophage M2 to M1 repolarization.

The present study aimed to validate the potential of a novel serine protein protease inhibitor (PPI), purified from marine Oceanimonas sp. BPMS22, induced M2 to M1 repolarization of the macrophages to treat visceral leishmaniasis (VL). Peptide mass fingerprint of the purified trypsin digested PPI peptide was obtained using matrix-assisted laser desorption ionization-time of flight combined with tandem mass spectrometry (MALDI-TOF MS/MS) and the sequence was used to construct a 3D protein model by homology modelling. The IC50 of PPI were 25.28 ± 1.675 µg/mL and 0.415 ± 0.015 µg/mL against promastigotes and intracellular amastigotes, respectively, indicating the host-directed therapy using PPI. The PPI enhanced the effector molecule i.e., nitric oxide (NO), and dampened the arginase activity in a dose-dependent manner. In vitro studies revealed that the BPMS22-derived PPI significantly (p < 0.05) decreased the mRNA expressions of M2 markers (FIZZ-1, YM-1, CD206, Arg-1) and increased the mRNA expressions of M1 markers (iNOS, IL-1ß, IL-12) in rIL-4 + rIL-10 induced M2 macrophages. Interestingly, the BPMS22-derived PPI also significantly (p < 0.05) decreased the FIZZ-1, YM-1, CD206, and Arg-1; significantly (p < 0.05) increased iNOS, IL-12, and IFN-γ mRNA expression in L. donovani -infected murine macrophages, alongside the decreased parasite load in it. Hence, PPI has the potential to repolarize the cytokines (rIL-4 + rIL-10) pre-stimulated and L. donovani-infected M2 macrophages to M1 phenotype in vitro. A decrease in parasite burden after treatment with PPI indicated the acceleration of the parasite killing by enhancing the macrophage effector functions. Further, in vivo PPI treatment reduced hepatic and splenic Leishman donovan units (LDU) up to 93.34 % and 87.63 %, respectively. This was followed by a surge in pro-inflammatory cytokines and dampening anti-inflammatory cytokines (p < 0.01), which exhibited anti-VL immunity. These observations might open new perspectives on PPI in macrophage repolarization to treat VL.

Anti-virulence properties of catechin-in-cyclodextrin-in-phospholipid liposome through down-regulation of gene expression in MRSA strains.

Methicillin resistant Staphylococcus aureus (MRSA) is a prime pathogen responsible for various infections in human beings. Expression of virulence factors is a biggest challenge in MRSA, which results in failure of conventional antibiotic therapy. In connection to the search for natural and safe anti-virulence compounds, the present study focused to evaluate the anti-virulence potential of catechin-in-cyclodextrin-in-phospholipid liposome (CCPL) on MRSA strains. CCPL inhibited young biofilm (64.15-72.70%) as well degraded mature biofilm (55.60-63.65%) at ½ and » MIC doses, which was further confirmed by scanning electron microscopy and confocal laser scanning microscope studies. CCPL was capable enough to modify the surface hydrophobicity (40.26-48.59%), reduce the EPS production (1.71-2.25 folds) and bacterial motility. In addition, CCPL inhibited the synthesis of virulence factors like slime production (0.40-0.50 folds), DNase production, hemolytic activity (28.08-49.07%), proteolytic production (14.65-18.04%), lipase production, autolysis and cell auto-aggregation. CCPL prevented the staphyloxanthin production and thereby increased the susceptibility of MRSA strains towards H2O2. Further, CCPL significantly down-regulated the virulence genes (agrA, agrC, clfA, clfB, fnbA, fnbB, icaA, icaD, hla, hld, rna III, atlA, sarA, sigB & geh). Thus, the results of present study revealed that the CCPL can effectively reduce the virulence properties and its application could inhibit the pathogenicity and also prevents the development of drug-resistance in MRSA strains.

Vitexin isolated from Prosopis cineraria leaves induce apoptosis in K-562 leukemia cells via inhibition of the BCR-ABL-Ras-Raf pathway.

OBJECTIVES: Leukemia is one of the severe cancer types all around the globe. Even though some chemotherapeutic drugs are available for treating leukemia, they have various side effects. As an alternative approach, herbal drugs are focused on current research to overcome leukemia. The present work was conducted to investigate the antileukemic mechanism of active phytochemical vitexin, which was isolated from ethno-medicine (Prosopis cineraria leaf) used by traditional healers of West Bengal, India. METHODS: Antiproliferative mechanisms of selected phyto-compound against K-562 cells were evaluated using cellular uptake, morphological changes, DNA fragmentation, mitochondrial membrane potential and signaling pathways analysis. KEY FINDINGS: Vitexin exhibited cytotoxicity by reducing mitochondrial membrane potential (32.40%) and causing DNA fragmentation (84.15%). The western blotting study indicated inhibition of cell survival proteins (BCR, ABL, H-RAS, N-RAS, K-RAS and RAF) and expression of apoptotic proteins (p38, BAX and caspase-9) in leukemia cells upon treatment with vitexin. CONCLUSIONS: Based on the results, presently investigated phyto-compound vitexin could be considered for developing safe and natural drugs to treat leukemia after conducting suitable preclinical and clinical trials.

Dynamicity in Host Metabolic Adaptation Is Influenced by the Synergistic Effect of Eugenol Oleate and Amphotericin B During Leishmania donovani Infection In Vitro.

Immune metabolic adaptation in macrophages by intracellular parasites is recognized to play a crucial role during Leishmania infection. However, there is little accessible information about changes in a metabolic switch in L. donovani infected macrophages. In previous studies, we have reported on the anti-leishmanial synergic effect of eugenol oleate with amphotericin B. In the present study, we demonstrated that glycolytic enzymes were highly expressed in infected macrophages during combinatorial treatment of eugenol oleate (2.5 µM) and amphotericin B (0.3125 µM). Additionally, we found that the biphasic role in arachidonic acid metabolite, PGE2, and LTB4, is released during this treatment. In vitro data showed that COX-2 mediated PGE2 synthesis increased significantly (p<0.01) in infected macrophages. Not only was the level of prostaglandin synthesis decreased 4.38 fold in infected macrophages after treatment with eugenol oleate with amphotericin B. The mRNA expression of PTGES, MPGES, and PTGER4 were also moderately expressed in infected macrophages, and found to be decreased in combinatorial treatment. In addition, NOS2 expression was activated by the phosphorylation of p38MAPK when combination-treated macrophages were promoted to kill intracellular parasites. The findings of the present study indicate that the synergism between eugenol oleate and amphotericin B could play an important role in immune metabolism adaptation with a concomitant increase in host immune response against the intracellular pathogen, L. donovani.

Apoptotic mechanisms of myricitrin isolated from Madhuca longifolia leaves in HL-60 leukemia cells.

Myricitrin, a naturally occurring flavonoid in Madhuca longifolia, possesses several medicinal properties. Even though our earlier work revealed its role against the proliferation of acute myelogenous leukemia cells (HL-60), its molecular mechanisms have not yet been revealed. The current study aims to explore the molecular mechanisms of myricitrin (isolated from an ethnomedicinal drug Madhuca longifolia) to induce apoptosis in HL-60 cells. Treatment with IC-50 dose of myricitrin (353 µM) caused cellular shrinkage and cell wall damage in HL-60 cells compared to untreated control cells. Myricitrin treatment reduced the mitochondrial membrane potential (22.95%), increased DNA fragmentation (90.4%), inhibited the cell survival proteins (RAS, B-RAF, & BCL-2) and also induced pro-apoptotic proteins (p38, pro-caspase-3, pro-caspase-9 and caspase-3) in the HL-60 cells. The present study provides scientific evidence for the apoptosis caused by myricitrin in HL-60 leukemia cells. Hence, the phytochemical myricitrin could be considered as a potential candidate to develop an anticancer drug after checking its efficacy through suitable pre-clinical and clinical studies.

Oral combination of eugenol oleate and miltefosine induce immune response during experimental visceral leishmaniasis through nitric oxide generation with advanced cytokine demand.

Conventional therapy of visceral leishmaniasis (VL) remains challenging with the pitfall of toxicity, drug resistance, and expensive. Hence, urgent need for an alternative approach is essential. In this study, we evaluated the potential of combination therapy with eugenol oleate and miltefosine in Leishmania donovani infected macrophages and in the BALB/c mouse model. The interactions between eugenol oleate and miltefosine were found to be additive against promastigotes and amastigotes with xΣFIC 1.13 and 0.68, respectively. Significantly (p < 0.001) decreased arginase activity, increased nitrite generation, improved pro-inflammatory cytokines, and phosphorylated p38MAPK were observed after combination therapy with eugenol oleate and miltefosine. >80% parasite clearance in splenic and hepatic tissue with concomitant nitrite generation, and anti-VL cytokines productions were observed after orally administered miltefosine (5 mg/kg body weight) and eugenol oleate (15 mg/kg body weight) in L. donovani-infected BALB/c mice. Altogether, this study suggested the possibility of an oral combination of miltefosine with eugenol oleate against visceral leishmaniasis.

Synergic effect of eugenol oleate with amphotericin B augments anti-leishmanial immune response in experimental visceral leishmaniasis in vitro and in vivo.

Present treatment regimen on visceral leishmaniasis has multiple limitations including severe side effects, toxicity, and resistance of Leishmania strains. Amphotericin B is a well-established pharmacologically approved drug; however, mainly toxicity is a foremost issue with that drug. Recently, our group identified eugenol oleate as an anti-leishmanial immunomodulatory compound. The important objectives of this present study was to evaluate the possible synergistic effect of eugenol oleate with amphotericin B to reduce the toxicity of this approved drug. Results obtained from this study signified that combination of eugenol oleate and amphotericin B showed indifferent combinatorial effect against promastigotes with xΣFIC 1.015, while, moderate synergistic activity with xΣFIC 0.456 against amastigotes. It was also notable that eugenol oleate (2.5 µM) with low concentrations of amphotericin B (0.3125 µM) showed 96.45% parasite reduction within L. donovani-infected murine macrophages. Furthermore, eugenol oleate and amphotericin B significantly (p < 0.01) enhanced the nitrite generation, and pro-inflammatory cytokines (IL-12, IFN-γ and TNF-α) in infected macrophages in vitro and in BALB/c mice in vivo. Eugenol oleate (10 mg/Kg b. wt.) with amphotericin B (1 mg/Kg b.wt.) significantly (p < 0.01) controlled the parasite burden in liver by 96.2% and in spleen by 93.12%. Hence, this study strongly suggested the synergic potential of eugenol oleate with low concentration of amphotericin B in experimental visceral leishmaniasis through anti-leishmanial immune response.