C-Terminal Domain Deletion Enhances the Protective Activity of cpa/cpb Loaded Solid Lipid Nanoparticles against Leishmania major in BALB/c Mice

Cutaneous leishmaniasis (CL) is the most common form of leishmaniasis with an annual incidence of approximately 2 million cases and is endemic in 88 countries, including Iran. CL's continued spread, along with rather ineffectual treatments and drug-resistant variants emergence has increased the need for advanced preventive strategies. We studied Type II cysteine proteinase (CPA) and Type I (CPB) with its C-terminal extension (CTE) as cocktail DNA vaccine against murine and canine leishmaniasis. However, adjuvants' success in enhancing immune responses to selected antigens led us to refocus our vaccine development programs. Herein, we discuss cationic solid lipid nanoparticles' (cSLN) ability to improve vaccine-induced protective efficacy against CL and subsequent lesion size and parasite load reduction in BALB/c mice. For this work, we evaluated five different conventional as well as novel parasite detection techniques, i.e., footpad imaging, footpad flowcytometry and lymph node flowcytometry for disease progression assessments. Vaccination with cSLN-cpa/cpb-CTE formulation showed highest parasite inhibition at 3-month post vaccination. Immunized mice showed reduced IL-5 level and significant IFN-ã increase, compared to control groups. We think our study represents a potential future and a major step forward in vaccine development against leishmaniasis

Prolyl hydroxylase-1 negatively regulates IκB kinase-β, giving insight into hypoxia-induced NFκB activity

Hypoxia is a feature of the microenvironment of a growing tumor. The transcription factor NFκB is activated in hypoxia, an event that has significant implications for tumor progression. Here, we demonstrate that hypoxia activates NFκB through a pathway involving activation of IκB kinase-β (IKKβ) leading to phosphorylation-dependent degradation of IκBα and liberation of NFκB. Furthermore, through increasing the pool and/or activation potential of IKKβ, hypoxia amplifies cellular sensitivity to stimulation with TNFα. Within its activation loop, IKKβ contains an evolutionarily conserved LxxLAP consensus motif for hydroxylation by prolyl hydroxylases (PHDs). Mimicking hypoxia by treatment of cells with siRNA against PHD-1 or PHD-2 or the pan-prolyl hydroxylase inhibitor DMOG results in NFκB activation. Conversely, overexpression of PHD-1 decreases cytokine-stimulated NFκB reporter activity, further suggesting a repressive role for PHD-1 in controlling the activity of NFκB. Hypoxia increases both the expression and activity of IKKβ, and site-directed mutagenesis of the proline residue (P191A) of the putative IKKβ hydroxylation site results in a loss of hypoxic inducibility. Thus, we hypothesize that hypoxia releases repression of NFκB activity through decreased PHD-dependent hydroxylation of IKKβ, an event that may contribute to tumor development and progression through amplification of tumorigenic signaling pathways