Intracellular pathogens belonging to the genus Leishmania have developed effective strategies that enable them to survive within host immune cells. Immunostimulatory compounds that counteract such immunological escape mechanisms represent promising treatment options for diseases. Here, we demonstrate that a lipopeptidephosphoglycan (LPPG) isolated from the membrane of a protozoan parasite, Entamoeba histolytica (Eh), shows considerable immunostimulatory effects targeted against Leishmania (L.) major, a representative species responsible for cutaneous leishmaniasis (CL). Treatment led to a marked reduction in the number of intracellular Leishmania parasites in vitro, and ameliorated CL in a mouse model. We next designed and synthesized analogs of the phosphatidylinositol anchors harbored by EhLPPG; two of these analogs reproduced the anti-leishmanial activity of the native compound by inducing production of pro-inflammatory cytokines. The use of such compounds, either alone or as a supportive option, might improve the currently unsatisfactory treatment of CL and other diseases caused by pathogen-manipulated immune responses.

glycolipid, immune response, leishmania, phosphatidylinositol, parasites, Entamoeba histolytica, Parasite, protozoan, cutaneous leishmaniasis, Leishmaniasis

There are 2 chemically distinct structures. Please, select:
lXMon?(1-1)[lXPam?(1-2)xLmyoIno?(1-P-3)]x?Gro? LIP(1-1)[lXPam?(1-2)xLmyoIno?(1-P-3)]x?Gro?

SVGMWSMILES3D molIonize

 

CCCCCCCCCCCCCCCCCCCCCCCCCCCC(=O)OCC(O)COP(=O)(O)O[C@@H]1[C@@H](O)[C@H](O)[C@@H](O)[C@H](O)[C@@H]1OC(=O)CCCCCCCCCCCCCCC

979.368 g/mol (C₅₃H₁₀₃O₁₃P)

Intracellular pathogens belonging to the genus Leishmania have developed effective strategies that enable them to survive within host immune cells. Immunostimulatory compounds that counteract such immunological escape mechanisms represent promising treatment options for diseases. Here, we demonstrate that a lipopeptidephosphoglycan (LPPG) isolated from the membrane of a protozoan parasite, Entamoeba histolytica (Eh), shows considerable immunostimulatory effects targeted against Leishmania (L.) major, a representative species responsible for cutaneous leishmaniasis (CL). Treatment led to a marked reduction in the number of intracellular Leishmania parasites in vitro, and ameliorated CL in a mouse model. We next designed and synthesized analogs of the phosphatidylinositol anchors harbored by EhLPPG; two of these analogs reproduced the anti-leishmanial activity of the native compound by inducing production of pro-inflammatory cytokines. The use of such compounds, either alone or as a supportive option, might improve the currently unsatisfactory treatment of CL and other diseases caused by pathogen-manipulated immune responses.

glycolipid, immune response, leishmania, phosphatidylinositol, parasites, Entamoeba histolytica, Parasite, protozoan, cutaneous leishmaniasis, Leishmaniasis

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

R1 = LIP
[1*]OCC(O)COP(=O)(O)O[C@@H]1[C@@H](O)[C@H](O)[C@@H](O)[C@H](O)[C@@H]1O

333.206 g/mol (C₉H₁₈RO₁₁P, R = residue superclass(es), not counted in mol weight)

The present study aimed to evaluate the influence of ultrasound assisted H2O2/ascorbic acid reaction on the structural characteristic and immunostimulatory activity of a β-D-glucan isolated from D. indusiata, so as to reveal its potential structure-immunostimulatory activity relationship. A purified β-D-glucan, named as DP, was quickly isolated from D. indusiata, and further identified as a 1,3-β-D-glucan with 1,6-β-D-Glcp as branched chains, which exhibited a rigid rod chain conformation in 0.9 % (w/v) of NaCl solution. Furthermore, results showed that the primary structure of DP was overall stable after the degradation by ultrasound assisted H2O2/ascorbic acid reaction. However, the molar mass and chain conformation of DP obviously changed. In addition, DP and its degraded products exerted remarkable immunostimulatory activity in vitro and in vivo, which could activate the nuclear factor-κB (NF-κB) signaling pathway through toll-like receptor 4 (TLR4). Indeed, the immunostimulatory activity of DP was closely-correlated to its molar mass and chain conformation. An appropriate degradation of molar mass could promote its immunostimulatory activity. While the transformation of chain conformation from rigid rod to random coil could cause the significant decrease of its immunostimulatory activity. These findings are beneficial to better understanding the structure-immunostimulatory activity relationship of β-D-glucans from edible mushrooms.

β-glucan, Chain conformation, molar mass, Immunostimulatory activity, Dictyophora indusiata, ultrasound assisted H(2)O(2)/ascorbic acid reaction

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
3,3,3,3	bDGlcp	103.55	73.06	86.57	69.16	76.63	61.40
3,3,3,6	bDGlcp	103.55	74.21	76.63	70.45	77.28	61.22
3,3,3	bDGlcp	103.32	73.06	86.57	69.16	75.06	69.16
3,3	bDGlcp	103.55	73.06	86.57	69.16	76.63	61.40
3,6	bDGlcp	103.55	74.21	76.63	70.45	77.28	61.22
3	bDGlcp	103.32	73.06	86.57	69.16	75.06	69.16
	bDGlcp	103.55	73.06	86.57	69.16	76.63	61.40


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
3,3,3,3	bDGlcp	4.53	3.35	3.48	3.28	3.35	3.43-3.68
3,3,3,6	bDGlcp	4.21	2.99	3.16	3.06	3.10	3.48-3.68
3,3,3	bDGlcp	4.53	3.35	3.48	3.28	3.48	3.48-4.11
3,3	bDGlcp	4.53	3.35	3.48	3.28	3.35	3.43-3.68
3,6	bDGlcp	4.21	2.99	3.16	3.06	3.10	3.48-3.68
3	bDGlcp	4.53	3.35	3.48	3.28	3.48	3.48-4.11
	bDGlcp	4.53	3.35	3.48	3.28	3.35	3.43-3.68


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
3,3,3,3	bDGlcp	103.55/4.53	73.06/3.35	86.57/3.48	69.16/3.28	76.63/3.35	61.40/3.43-3.68
3,3,3,6	bDGlcp	103.55/4.21	74.21/2.99	76.63/3.16	70.45/3.06	77.28/3.10	61.22/3.48-3.68
3,3,3	bDGlcp	103.32/4.53	73.06/3.35	86.57/3.48	69.16/3.28	75.06/3.48	69.16/3.48-4.11
3,3	bDGlcp	103.55/4.53	73.06/3.35	86.57/3.48	69.16/3.28	76.63/3.35	61.40/3.43-3.68
3,6	bDGlcp	103.55/4.21	74.21/2.99	76.63/3.16	70.45/3.06	77.28/3.10	61.22/3.48-3.68
3	bDGlcp	103.32/4.53	73.06/3.35	86.57/3.48	69.16/3.28	75.06/3.48	69.16/3.48-4.11
	bDGlcp	103.55/4.53	73.06/3.35	86.57/3.48	69.16/3.28	76.63/3.35	61.40/3.43-3.68

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

*O[C@H]1[C@H](O)[C@@H](CO)O[C@@H](O[C@@H]2[C@@H](O)[C@H](O[C@@H]3[C@@H](O)[C@H](O[C@@H]4[C@@H](O)[C@H](O[C@@H]5[C@@H](O)[C@H](*)O[C@H](CO)[C@H]5O)O[C@H](CO[C@@H]5O[C@H](CO)[C@@H](O)[C@H](O)[C@H]5O)[C@H]4O)O[C@H](CO)[C@H]3O)O[C@H](CO[C@@H]3O[C@H](CO)[C@@H](O)[C@H](O)[C@H]3O)[C@H]2O)[C@@H]1O

1134.987 g/mol (C₄₂H₇₀R₂O₃₅, R = next and previous repeats, not counted in mol weight)