Inflammation induced by phytomodulatory proteins from the latex of Calotropis procera (Asclepiadaceae) protects against Salmonella infection in a murine model of typhoid fever

Novel yeasts with potential probiotic characteristics isolated from the endogenous ferment of artisanal Minas cheese

Artisanal Minas cheese (QMA) is traditionally elaborate using raw milk and endogenous ferment (pingo - whey or rala - grated ripened cheese). In the present study, 91 yeast strains were isolated and identified from pingo and rala. Eight yeast species were identified by the MALDI-TOF mass spectrometry and confirmed by sequencing of the ITS region. The yeasts' protease and lipase activities were evaluated in addition to probiotic properties such as tolerance to low pH and bile salts, hydrophobicity, autoaggregation, co-aggregation with pathogens, and antimicrobial susceptibility. The rala ferment showed a greater variety of species. Yarrowia lipolytica was the dominant specie (52.7% of isolates), followed by the Kluyveromyces lactis and Kodamaea ohmeri (9.9 and 6.6%, respectively). From the total yeasts evaluated, 74 strains showed positive enzymatic activity: 52 strains showed lipolytic (51 Y. lipolytica and one Trichosporon japonicum) and 44 proteolytic activities (18 Y. lipolytica, 13 K. ohmeri, 11 K. lactis, and 2 Wickerhamiella sp.). All evaluated isolates demonstrated tolerance to pH 2.0, and 69 isolates supported the presence of bile salts. From them, 12 isolates showed the capacity of autoaggregation (> 30%) and hydrophobicity (> 90.0%) and were then selected for co-aggregation and antibiotic resistance assays. All selected isolates showed co-aggregation with Salmonella Enteritidis, Escherichia coli, and Listeria monocytogenes greater than 30%. None of the yeast showed sensibility to the evaluated antibiotics and antagonistic activity against the evaluated pathogens. The results demonstrated that pingo and rala have different yeast composition with different enzymatic activity, which may affect the characteristics of the cheese. Furthermore, some yeast strains: Y. lipolytica (9 strains isolated from rala) and K. ohmeri (3 strains isolated from pingo) demonstrated attractive probiotic potential.

Perspectives for the use of latex peptidases from Calotropis procera for control of inflammation derived from Salmonella infections

BACKGROUND

Anti-inflammatory properties have been attributed to latex proteins of the medicinal plant Calotropis procera.

PURPOSE

A mixture of cysteine peptidases (LPp2) from C. procera latex was investigated for control of inflammatory mediators and inflammation in a mouse model of Salmonella infection.

METHODS

LPp2 peptidase activity was confirmed by the BANA assay. Cytotoxicity assays were conducted with immortalized macrophages. Peritoneal macrophages (pMØ) from Swiss mice were stimulated with lipopolysaccharide (LPS) in 96-well plates and then cultured with nontoxic concentrations of LPp2. Swiss mice intravenously received LPp2 (10 mg/kg) and then were challenged intraperitoneally with virulent Salmonella enterica Ser. Typhimurium.

RESULTS

LPp2 was not toxic at dosages lower than 62.2 μg/mL. LPp2 treatments of pMØ stimulated with LPS impaired mRNA expression of pro-inflammatory cytokines IL-1β, TNF-α, IL-6 and IL-10. LPp2 increased the intracellular bacterial killing in infected pMØ. Mice given LPp2 had a lower number of leukocytes in the peritoneal cavity in comparison to control groups 6 h after infection. The bacterial burden and histological damage were widespread in target organs of mice receiving LPp2.

CONCLUSION

We conclude that LPp2 contains peptidases with strong anti-inflammatory properties, which may render mice more susceptible to early disseminated infection caused by Salmonella.

Latex proteins downregulate inflammation and restores blood-coagulation homeostasis in acute Salmonella infection

BACKGROUND

Calotropis procera latex protein fraction (LP) was previously shown to protect animals from septic shock. Further investigations showed that LP modulate nitric oxide and cytokines levels.

OBJECTIVES

To evaluate whether the protective effects of LP, against lethal bacterial infection, is observed in its subfractions (LP_PII and LP_PIII).

METHODS

Subfractions (5 and 10 mg/kg) were tested by i.p. administration, 24 h before challenging with lethal injection (i.p.) of Salmonella Typhimurium. LP_PIII (5 mg/kg) which showed higher survival rate was assayed to evaluate bacterial clearance, histopathology, leukocyte recruitment, plasma coagulation time, cytokines and NO levels.

FINDINGS

LP_PIII protected 70% of animals of death. The animals given LP_PIII exhibited reduced bacterial load in blood and peritoneal fluid after 24 h compared to the control. LP_PIII promoted macrophage infiltration in spleen and liver. LP_PIII restored the coagulation time of infected animals, increased IL-10 and reduced NO in blood.

MAIN CONCLUSIONS

LP_PIII recruited macrophages to the target organs of bacterial infection. This addressed inflammatory stimulus seems to reduce bacterial colonisation in spleen and liver, down regulate bacterial spread and contribute to avoid septic shock.

Erythrocytes morphology and hemorheology in severe bacterial infection

BACKGROUND

Severe bacterial infections initiate inadequate inflammation that leads to disseminated intravascular coagulation and death.

OBJECTIVES

To evaluate the influence of bacterial infection on blood viscosity and red blood cells (RBCs) morphology, and the ability of Calotropis procera proteins (CpLP) to prevent the patho-hemorheology in infected animals.

METHODS

Rheology of blood, atomic force microscopy measurements on specific blood elements and blood count were performed to examine changes in blood viscosity, RBCs morphology, platelets activation, and RBCs indices.

FINDINGS

Infected mice hold their blood rheological behaviour as compared to that of the control group. However, they presented hyperactivated platelets, RBCs at different stages of eryptosis, and variation on RBCs indices. CpLP administration in healthy animals altered blood behaviour from pseudoplastic to Bingham-like fluid. Such effect disappeared over time and by inhibiting its proteases. No alterations were observed in RBCs morphology or platelets. Treatment of infected animals with CpLP prevented the changes in RBCs indices and morphology.

MAIN CONCLUSIONS

The inflammatory process triggered by bacterial infection induced pathological changes in RBCs and platelets activation. Treatment of infected animals with CpLP prevented the emergence of RBCs abnormal morphology and this may have implications in the protective effect of CpLP, avoiding animal death.

Using Molecular Docking Analysis to Discovery Dregea sinensis Hemsl. Potential Mechanism of Anticancer, Antidepression, and Immunoregulation

Background:

Dregea sinensis Hemsl. plant of the genus Dregea volubilis (Asclepiadaceae), plays a vital role in anticancer, antidepression, and immunoregulation. Steroidal glycosides are the main constituents of this herb, which were significant biological active ingredients.

Objective:

The objective of this study is to recognize the mechanism of anticancer, antidepression, and immunoregulation of D. sinensis Hemsl.

Materials and Methods:

Seventy-two steroidal glycosides of D. sinensis Hemsl. were evaluated on the docking behavior of tumor-associated proteins (PI3K, Akt, mTOR), depression-related proteins (MAO-A, MAO-B) and immune-related proteins (tumor necrosis factor-α [TNF-α], tumor necrosis factor receptor 2 [TNFR2], interleukin-2Rα [IL-2Rα]) using Discovery Studio version 3.1 (Accelrys, San Diego, USA).

Results:

The molecular docking analysis revealed that mostly steroidal glycosides of D. sinensis Hemsl. exhibited powerful interaction with the depression-related protein (MAO-A) and the immune-related proteins (TNFR2, IL-2Rα). Some ligands exhibited high binding energy for the tumor-associated proteins (PI3K, Akt, mTOR) and the immune-related protein (TNF-α), but MAO-B showed none interaction with the ligands.

Conclusion:

This study has paved better understanding of steroidal glycosides from D. sinensis Hemsl. as potential constituents to the prevention of associated cancer, depression and disorders of immunoregulation.

SUMMARY

The ligand database was consist of 72 steroidal glycosides from Dregea sinensis Hemsl

Steroidal glycosides had the potential to dock with the tumor-associated proteins (PI3K, Akt, mTOR)

Steroidal glycosides were bounded with MAO-A rather than MAO-B, accorded with the inhibitor selectivity of MAOs, can be considered as potent candidate inhibitors of MAO-A

72 ligands got high interaction with TNFR2 and IL-2Rα, regard the steroidal glycoside as powerful candidate inhibitors of TNFR2 and IL-2Rα.

Abbreviations used: PI3K: Phosphatidyl inositol 3-kinase; Akt: Protein kinase B; mTOR: Mammalian target of rapamycin; MAO-A: Monoamine oxidase A; MAO-B: Monoamine oxidase B; TNF-α: Tumor necrosis factor α; TNFR2: Tumor necrosis factor receptor 2; IL-2Rα: The alpha subunit (CD25) of the interleukin-2 receptor; DS: Discovery Studio; PDB: Protein Database Bank; 3D: three-dimensional.

Plant lectins ConBr and CFL modulate expression toll-like receptors, pro-inflammatory cytokines and reduce the bacterial burden in macrophages infected with Salmonella enterica serovar Typhimurium

BACKGROUND

Plant lectins have long been used in biomedical research as immunomodulators against tumor cells and microbial infections.

PURPOSE

To test the ability of plant lectins ConBr (Canavalia brasiliensis) and CFL (Cratylia argentea) to activate antimicrobial and immunomodulatory activities of murine peritoneal macrophages (pMØ) infected with a virulent strain of Salmonella enterica serovar Typhimurium (STm).

METHODS

We incubated pMØ with non-toxic amounts of ConBr and CFL either before (preventive schedule) or after (curative schedule) exposure to STm.

RESULTS

In uninfected pMØ, ConBr and CFL greatly increased levels of mRNA transcripts for IL-1β, TNF-α and IL-6 and the inducible nitric oxide synthase (iNOs), but not IL-10 and IL-12. Exposure to naïve splenocytes of culture supernatants of pMØ previously stimulated with CFL resulted in expression of IL-12 and IFN-γ. Both preventive and curative treatment schedules significantly reduced the intracellular load of Salmonella. Experiments in infected macrophages exposed to lectins in the preventive schedule showed that mRNA transcripts for IL-6 and TNF-α were increased by CFL, whereas ConBr enhanced IL-12 (subunit p40). In the curative schedule, CFL induced significant expression of IL-12 (p40) whereas ConBr enhanced expression IL-1β and TNF-α genes. The lectin treatments did not influence on iNOs expression in pMØ infected with STm C5 regardless of the treatment schedule. Curative treatments with CFL increased approximately 130-fold expression of TLR-4 whist expression of TLR-9 was increased by treatments with ConBr.

CONCLUSION

We conclude that lectins ConBr and CFL have immunomodulatory properties that are beneficial on control of cells infected by Salmonella.

Latex protein extracts from Calotropis procera with immunomodulatory properties protect against experimental infections with Listeria monocytogenes

BACKGROUND

The latex from the medicinal plant Calotropis procera is often used in folk medicine against infectious and inflammatory diseases.

PURPOSE

In this study, we investigate a protein fraction with immunomodulatory properties, named LPPI, against experimental infections, in vitro and in vivo, with a virulent strain of Listeria monocytogenes.

STUDY DESIGN

LPPI was exposed to cultured macrophages or Swiss mice and then challenged with L. monocytogenes.

METHODS

Peritoneal macrophages were obtained from Swiss mice, and cultured in 96-well microplates. Soluble latex proteins (LP) were subjected to fractionation by ion-exchange chromatography. The major peak (LPPI) was added into wells at 10 or 100µg/ml. Albumin (100µg/ml) was used for comparison between protein treatments. After incubation for 1h at 5% CO2/ 37°C, the supernatant was discarded and 0.2ml of L. monocytogenes overnight culture was added in the wells. Following 4h and 24h infection, the cytokine mRNA expression was evaluated as well as the number of intracellular colony forming units. Swiss mice (n=16) were injected intraperitoneally (i.p.) with LPPI (5 and 10mg/kg) while the control mice received albumin (10mg/kg) or LP (10mg/kg). After 24h, all animal groups were challenged with L. monocytogenes (10(6) CFU/ ml), also by i.p. route.

RESULTS

LPPI was not toxic to uninfected macrophages (pMØ) and significantly increased mRNA expression of TNF-α, IL-6, IL-1β and iNOS. Following infection, cell viability was reduced by 50% in albumin-treated pMØ (control); but only 17% in pMØ treated with LPPI at 100µg/ml. In this case, LPPI increased expression of TNF-α and IL-6 whereas the number of bacterial colony-forming units was reduced 100-fold in comparison to control groups. Swiss mice pretreated with LPPI showed dose-dependent survival rates that reached 80%, while mice that received albumin died 1-3 days after infection. After 24h infection, leukocyte migration to the infectious foci was high in LPPI-treated mice whereas the number of viable bacteria in the peritoneal fluid, liver and bloodstream were significantly reduced.

CONCLUSION

We conclude that LPPI present immunomodulatory properties that are beneficial for prevention of systemic bacterial infections caused by the intracellular bacteria L. monocytogenes.

Peptidases from latex of Carica candamarcensis upregulate COX-2 and IL-1 mRNA transcripts against Salmonella enterica ser. Typhimurium-mediated inflammation

The immunomodulatory properties of a mixture of cysteine peptidases (P1G10) obtained from the fruit lattice of Carica candamarcensis were investigated. P1G10 was obtained from fresh latex samples by chromatography in a Sephadex column and initially administered to Swiss mice (n = 5; 1 or 10 mg/kg) via i.p. After 30 min, the mice were injected with carrageenan (0.5 mg/mouse) or heat-killed S. Typhimurium (10(7) CFU/mL; 100°C/30 min) into the peritoneal cavity. Afterwards, two animal groups were i.p. administered with P1G10 (n = 6; 1, 5, or 10 mg/Kg) or PBS 24 hours prior to challenge with live S. Typhimurium (10(7) CFU/mL). P1G10 stimulated the proliferation of circulating neutrophils and lymphocytes, 6 h after injection of carrageenan or heat-killed bacteria, respectively. Furthermore, survival after infection was dose-dependent and reached 60% of the animal group. On the other hand, control mice died 1-3 days after infection. The examination of mRNA transcripts in liver cells 24 h after infection confirmed fold variation increases of 5.8 and 4.8 times on average for IL-1 and COX-2, respectively, in P1G10 pretreated mice but not for TNF-α, IL-10, γ-IFN and iNOS, for which the results were comparable to untreated animals. These data are discussed in light of previous reports.