MORÓN VÍCTOR GABRIEL
Congresos y reuniones científicas
Título:
UNVEILING THE ROLE OF LIPID METABOLISM IN ENHANCING ANTIGEN CROSS-PRESENTATION BY PERHEXILINE MALEATE STIMULATED DENDRITIC CELLS
Lugar:
San Luis
Reunión:
Congreso; LXXI Reunión de la Sociedad Argentina de Inmunología; 2023
Institución organizadora:
Sociedad Argentina de Inmunología
Resumen:
The immune response mediated by cytotoxic CD8+ T cells (CTLs) plays a pivotal
role in both tumor immunotherapy and defense against intracellular pathogens.
Dendritic cells (DCs) have the ability to internalize and present exogenous
antigens (Ag) via MHC I to activate naïve CD8+ T cells, a process termed crosspresentation.
Adjuvants are necessary to robust CTL response, especially in
subunit vaccines. However, due to the intricate nature of Ag cross-presentation
pathways, identifying therapeutic targets that can serve as adjuvants for
generating protective CTL responses has proven challenging. To address this,
we previously performed a high throughput screening of drug libraries approved
by international agencies. The aim was to identify novel compounds and
molecular pathways capable of enhancing Ag cross-presentation in DCs. Our
approach involved the adaptation of the B3Z presentation assay using the
JAWSII DC cell line and Ovalbumin (OVA) as the soluble Ag. In this study, we
elucidate the mechanisms underlying the enhancement of cross- presentation
by Perhexiline Maleate (PM), one of the five active compounds identified.
Notably, PM does not influence OVA internalization nor MHC I-surface
expression in JAWSII DCs. Moreover, incubating JAWSII DCs with PM led to
increased translocation of Ags from endosomes to the cytosol (p<0.001), an
essential step in cross-presentation. To assess the capability of PM-stimulated
DCs to activate naïve CD8 T cells, we co-cultured Flt3-L BMDCs pre-treated
with PM + OVA with CD8+ T cells purified from OT-I mice. After three days, our
observations indicated that PM-stimulated DCs activate naïve CD8+ T cells,
triggering proliferation (p<0.05), CD44 expression (p<0.05), and IFNγ
secretion.
PM is known to inhibit the mitochondrial enzyme carnitine palmitoyltransferase
1 (CPT1), thereby reducing fatty acid metabolism. In alignment with this, our
prior work demonstrated that PM augmented the presence of lipid bodies per
cell, which has previously been related to the ability of DC to cross-present Ags
by various researchers. Consequently, we evaluated the involvement of lipid
metabolism in the cross-presentation process. Firstly, we found that Etomoxir,
another CPT1 inhibitor, enhance OVA cross-presentation by JAWSII DCs
(p<0.01), implicating CPT1 as a potential target. Secondly, we discovered that
both TOFA, an inhibitor of Acetyl-CoA Carboxylase-α (ACCA), and
Xanthohumol, an inhibitor of diacylglycerol acyltransferase 1 (DGAT-1) and
DGAT-2, counteracted the increase in OVA cross-presentation observed in PMstimulated
JAWSII DCs (p<0.05 and p<0.01 respectively), without affecting
other active compounds.
Further studies will be engaged to completely understand the role of lipid
metabolism in the enhancing cross-presentation ability in PM-stimulated DCs.
role in both tumor immunotherapy and defense against intracellular pathogens.
Dendritic cells (DCs) have the ability to internalize and present exogenous
antigens (Ag) via MHC I to activate naïve CD8+ T cells, a process termed crosspresentation.
Adjuvants are necessary to robust CTL response, especially in
subunit vaccines. However, due to the intricate nature of Ag cross-presentation
pathways, identifying therapeutic targets that can serve as adjuvants for
generating protective CTL responses has proven challenging. To address this,
we previously performed a high throughput screening of drug libraries approved
by international agencies. The aim was to identify novel compounds and
molecular pathways capable of enhancing Ag cross-presentation in DCs. Our
approach involved the adaptation of the B3Z presentation assay using the
JAWSII DC cell line and Ovalbumin (OVA) as the soluble Ag. In this study, we
elucidate the mechanisms underlying the enhancement of cross- presentation
by Perhexiline Maleate (PM), one of the five active compounds identified.
Notably, PM does not influence OVA internalization nor MHC I-surface
expression in JAWSII DCs. Moreover, incubating JAWSII DCs with PM led to
increased translocation of Ags from endosomes to the cytosol (p<0.001), an
essential step in cross-presentation. To assess the capability of PM-stimulated
DCs to activate naïve CD8 T cells, we co-cultured Flt3-L BMDCs pre-treated
with PM + OVA with CD8+ T cells purified from OT-I mice. After three days, our
observations indicated that PM-stimulated DCs activate naïve CD8+ T cells,
triggering proliferation (p<0.05), CD44 expression (p<0.05), and IFNγ
secretion.
PM is known to inhibit the mitochondrial enzyme carnitine palmitoyltransferase
1 (CPT1), thereby reducing fatty acid metabolism. In alignment with this, our
prior work demonstrated that PM augmented the presence of lipid bodies per
cell, which has previously been related to the ability of DC to cross-present Ags
by various researchers. Consequently, we evaluated the involvement of lipid
metabolism in the cross-presentation process. Firstly, we found that Etomoxir,
another CPT1 inhibitor, enhance OVA cross-presentation by JAWSII DCs
(p<0.01), implicating CPT1 as a potential target. Secondly, we discovered that
both TOFA, an inhibitor of Acetyl-CoA Carboxylase-α (ACCA), and
Xanthohumol, an inhibitor of diacylglycerol acyltransferase 1 (DGAT-1) and
DGAT-2, counteracted the increase in OVA cross-presentation observed in PMstimulated
JAWSII DCs (p<0.05 and p<0.01 respectively), without affecting
other active compounds.
Further studies will be engaged to completely understand the role of lipid
metabolism in the enhancing cross-presentation ability in PM-stimulated DCs.
