The role of liposome-protamine-DNA nanoparticles containing CpG oligodeoxynucleotides in the course of infection induced by Leishmania major in BALB/c mice

Immunogenicity of Recombinant Lipid-Based Nanoparticle Vaccines: Danger Signal vs. Helping Hand

Infectious diseases are a predominant problem in human health. While the incidence of many pathogenic infections is controlled by vaccines, some pathogens still pose a challenging task for vaccine researchers. In order to face these challenges, the field of vaccine development has changed tremendously over the last few years. For non-replicating recombinant antigens, novel vaccine delivery systems that attempt to increase the immunogenicity by mimicking structural properties of pathogens are already approved for clinical applications. Lipid-based nanoparticles (LbNPs) of different natures are vesicles made of lipid layers with aqueous cavities, which may carry antigens and other biomolecules either displayed on the surface or encapsulated in the cavity. However, the efficacy profile of recombinant LbNP vaccines is not as high as that of live-attenuated ones. This review gives a compendious picture of two approaches that affect the immunogenicity of recombinant LbNP vaccines: (i) the incorporation of immunostimulatory agents and (ii) the utilization of pre-existing or promiscuous cellular immunity, which might be beneficial for the development of tailored prophylactic and therapeutic LbNP vaccine candidates.

The novel treatments based on tissue engineering, cell therapy and nanotechnology for cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is a global public health issue. Conventional treatments have substantial costs, side effects, and parasite resistance. Due to easy application and inexpensive cost, topical treatment is the optimal approach for CL. It could be used alone or with systemic treatments. Electrospun fibers as drug release systems in treating skin lesions have various advantages such as adjustable drug release rate, maintaining appropriate humidity and temperature, gas exchange, plasticity at the lesion site, similarity with the skin extracellular matrix (ECM) and drug delivery with high efficiency. Hydrogels are valuable scaffolds in the treatment of skin lesions. The important features of hydrogels include preserving unstable drugs from degradation, absorption of wound secretions, high biocompatibility, improving the re-epithelialization of the wound and preventing the formation of scars. One of the issues in local drug delivery systems for the skin is the low permeability of drugs in the skin. Polymeric scaffolds that are designed as microneedle patches can penetrate the skin and overcome this challenge. Also, drug delivery using nanocarriers increases the effectiveness of drugs in lower and more tolerable doses and reduces the toxicity of drugs. The application of cell therapy in the treatment of parasitic and infectious diseases has been widely investigated. The complexity of leishmaniasis treatment requires identifying new treatment options like cell therapy to overcome the disease. Topics investigated in this study include drug delivery systems based on tissue engineering scaffolds, nanotechnology and cell therapy-based studies to reduce the complications of CL.

Systems biology of autophagy in leishmanial infection and its diverse role in precision medicine

Autophagy is a contentious issue in leishmaniasis and is emerging as a promising therapeutic regimen. Published research on the impact of autophagic regulation on Leishmania survival is inconclusive, despite numerous pieces of evidence that Leishmania spp. triggers autophagy in a variety of cell types. The mechanistic approach is poorly understood in the Leishmania parasite as autophagy is significant in both Leishmania and the host. Herein, this review discusses the autophagy proteins that are being investigated as potential therapeutic targets, the connection between autophagy and lipid metabolism, and microRNAs that regulate autophagy and lipid metabolism. It also highlights the use of systems biology to develop novel autophagy-dependent therapeutics for leishmaniasis by utilizing artificial intelligence (AI), machine learning (ML), mathematical modeling, network analysis, and other computational methods. Additionally, we have shown many databases for autophagy and metabolism in Leishmania parasites that suggest potential therapeutic targets for intricate signaling in the autophagy system. In a nutshell, the detailed understanding of the dynamics of autophagy in conjunction with lipids and miRNAs unfolds larger dimensions for future research.

Nanotechnology-aided diagnosis, treatment and prevention of leishmaniasis

Leishmaniasis is a prevalent parasitic infection belonging to neglected tropical diseases. It is caused by Leishmania protozoan parasites transmitted by sandflies and it is responsible for increased morbidity/mortality especially in low- and middle-income countries. The lack of cheap, portable, easy to use diagnostic tools exhibiting high efficiency and specificity impede the early diagnosis of the disease. Furthermore, the typical anti-leishmanial agents are cytotoxic, characterized by low patient compliance and require long-term regimen and usually hospitalization. In addition, due to the intracellular nature of the disease, the existing treatments exhibit low bioavailability resulting in low therapeutic efficacy. The above, combined with the common development of resistance against the anti-leishmanial agents, denote the urgent need for novel therapeutic strategies. Furthermore, the lack of effective prophylactic vaccines hinders the control of the disease. The development of nanoparticle-based biosensors and nanocarrier-aided treatment and vaccination strategies could advance the diagnosis, therapy and prevention of leishmaniasis. The present review intends to highlight the various nanotechnology-based approaches pursued until now to improve the detection of Leishmania species in biological samples, decrease the side effects and increase the efficacy of anti-leishmanial drugs, and induce enhanced immune responses, specifically focusing on the outcome of their preclinical and clinical evaluation.

Development of nano-carriers for Leishmania vaccine delivery

Introduction: Leishmaniasis is a neglected tropical infection caused by several species of intracellular protozoan parasites of the genus Leishmania. It is strongly believed that the development of vaccines is the most appropriate approach to control leishmaniasis. However, there is no vaccine available yet and the lack of an appropriate adjuvant delivery system is the main reason.Areas covered: Adjuvants are the utmost important part of a vaccine, to induce the immune response in the right direction. Limitations and drawbacks of conventional adjuvants have been necessitated the development of novel particulate delivery systems as adjuvants to obtain desirable protection against infectious diseases such as leishmaniasis. This review focused on particulate adjuvants especially nanoparticles that are in use to develop vaccines against leishmaniasis. The list of adjuvants includes generally lipids-, polymers-, or mineral-based delivery systems that target antigens specifically to the site of action within the host's body and enhance immune responses.Expert opinion: Over the past few years, there has been an increasing interest in developing particulate adjuvants as alternatives to immunostimulatory types. The composition of nano-carriers and particularly the physicochemical properties of nanoparticles have great potential to overcome challenges posed to leishmaniasis vaccine developments.

Emerging therapeutic targets for treatment of leishmaniasis

INTRODUCTION

Parasitic diseases that pose a threat to human life include leishmaniasis - caused by protozoan parasite Leishmania species. Existing drugs have limitations due to deleterious side effects like teratogenicity, high cost and drug resistance. This calls for the need to have an insight into therapeutic aspects of disease. Areas covered: We have identified different drug targets via. molecular, imuunological, metabolic as well as by system biology approaches. We bring these promising drug targets into light so that they can be explored to their maximum. In an effort to bridge the gaps between existing knowledge and prospects of drug discovery, we have compiled interesting studies on drug targets, thereby paving the way for establishment of better therapeutic aspects. Expert opinion: Advancements in technology shed light on many unexplored pathways. Further probing of well established pathways led to the discovery of new drug targets. This review is a comprehensive report on current and emerging drug targets, with emphasis on several metabolic targets, organellar biochemistry, salvage pathways, epigenetics, kinome and more. Identification of new targets can contribute significantly towards strengthening the pipeline for disease elimination.

Enhanced immune response induced by P5 HER2/neu-derived peptide-pulsed dendritic cells as a preventive cancer vaccine

Dendritic cells are special and powerful antigen-presenting cells that can induce primary immune responses against tumour-associated antigens. They can present antigens via both MHC-I and MHC-II, so they have the ability to stimulate both cytotoxic T lymphocytes and T helper cells. Furthermore, CD8+ cytotoxic T lymphocytes require activation by CD4+ T cells. This requires a CD4+ T cell activator molecule, of which PADRE is one of the best. We chose an approach to use both of these important arms of the immune system. We prepared dendritic cells from mouse bone marrow, loaded them with our target peptides (P5 peptide alone or P5 + PADRE), and then injected these pulsed dendritic cells alone or in combination with CpG-ODN (as adjuvant) into BALB/C mice. After the last boosting dose, mice were inoculated with TUBO cells, which overexpress HER2/neu. Two weeks after the tumour cell injection, immunological tests were performed on splenocyte suspensions, and the remaining mice were evaluated for tumour growth and survival. Our data indicate the formulation that contains PADRE plus P5 loaded onto DC in combination with CpG-ODN was the most effective formulation at inducing immune responses. Interferon production in CD4+ and CD8+ gated cells, cytotoxicity rates of target cells and mice survival were all significantly greater in this group than in controls, and all the mice in this group were tumour-free throughout the experiment. Based on our results and the role of HER2/neu as a candidate in human immunotherapy, this approach may be an effective cancer treatment.

The role of LPD-nanoparticles containing recombinant major surface glycoprotein of Leishmania (rgp63) in protection against leishmaniasis in murine model

CONTEXT

Leishmaniasis is a major public health problem. Despite numerous attempts, yet there is no effective vaccine against human leishmaniasis, mainly due to a lack of an effective vaccine delivery system as well as adjuvant.

OBJECTIVE(S)

The aim of this study was to evaluate the ability of recombinant glycoprotein 63 (rgp63) as a model of Leishmania antigen, entrapped in liposome-polycation-DNA (LPD) complexes nanoparticles in inducing cell mediated immune (CMI) response and protecting against L. major in BALB/c mice.

MATERIALS AND METHODS

To this end, the abundant leishmania promastigote cell surface glycoprotein, gp63, was entrapped in nano-sized LPD (CpG) particles, (LPD (CpG)-rgp63), and BALB/c mice were immunized three times with either (LPD (CpG)-rgp63) or rgp63-CpG DNA or LPD (CpG) or free rgp63 and dextrose 5%. Various parameters including footpad thickness, splenic load of L. major parasites, rgp63-binding IgGs and also cytokine levels of rgp63-reactive T lymphocytes were then compared among different vaccinated animals.

RESULTS

The lowest number of parasites in spleen, the higher levels of IgG2a after challenge infection, the minimal footpad swelling and high level of IFN-γ secretion, all indicated that adjuvants and antigen-delivery systems are essential in modifying immune responses; as mice received LPD (CpG)-rgp63 induced immune response stronger than the other groups.

CONCLUSIONS

This study demonstrates that LPD nanoparticle is a promising and adaptable delivery system which could be modified towards specific vaccine targets to induce a more potent immune response in combination with rgp63.

Coadminstration of L. major amastigote class I nuclease (rLmaCIN) with LPD nanoparticles delays the progression of skin lesion and the L. major dissemination to the spleen in BALB/c mice-based experimental setting

Human cutaneous leishmaniasis is a disease caused by eukaryotic single-celled Leishmania species, the developmental program of which relies upon blood-feeding adult female sand flies and their dominant mammal blood sources, namely wild rodents in area where human beings exert more or less transient activities. The recourse to model rodents - namely laboratory mice such as C57BL/6 mice - has allowed extracted the immune signatures that account for the healing of the transient cutaneous lesion that develops at the site where Leishmania major promastigotes were delivered. Indeed, if the latter mice are exposed to a second inoculum of L. major promastigotes, no lesion will develop in the secondary skin site remodeled as a niche for a low size intracellular L. major amastigote population. Moreover, IFN-γ dominates over IL-10 in the supernatant of cultures of PBMCs -prepared from blood sampled from human beings who healed from a cutaneous lesion- and incubated with L. major class I Nuclease LmaCIN, a protein highly expressed in the cell-cycling amastigote population which is dominant by macrophages. Altogether, these datasets were strong incentive to promote research aimed to design and monitor efficacy of L. major amastigote protein-based vaccines in pre-clinical settings. Using L. major enzyme class I nuclease (LmaCIN) expressed in the L. major cell-cycling amastigote population hosted by macrophages, BALB/c mice were immunized three times with either rLmaCIN plus LPD nanoparticles (LPD-rLmaCIN), or rLmaCIN-CpG DNA or free rLmaCIN and dextrose. The following parameters: footpad swelling, splenic L. major load, L. major binding IgGs and cytokine profiles of rLmaCIN- reactive T lymphocytes were then compared. Once coadminstered with LPD, rLmaCIN allow BALB/c mice to display delayed onset of skin lesion at the challenge inoculation site and delayed L. major dissemination from the challenged site to the spleen. Thus, the LPD-rLmaCIN is shown to display some promising features out of three formulations inoculated to the BALB/c mouse immunization.

Evaluation of the in vivo leishmanicidal activity of amphotericin B emulgel: An alternative for the treatment of skin leishmaniasis

The American Cutaneous Leishmaniasis (ACL) is an infectious disease that can be fatal. The first line of treatment is pentavalent antimonies. However, due to its potential to develop resistance, Amphotericin B (AmB) started to be used as an alternative medicine. Current treatments are limited, a fact that has led to a growing interesting in developing new therapies. This study aims to evaluate the therapeutic potential in vivo of an amphotericin B + oleic acid (OA) emulgel in the treatment of cutaneous leishmaniasis in an experimental model. Strains of Leishmania major MHOM/IL/80/Friendlin of Leishmania major were used. The animals were inoculated subcutaneously. After the development of leishmanial, nodular or ulcerative lesions, the animals were divided into three groups (control, Group A and Group B) and treated twice a day for twelve days. The weight of the animals was measured and the size of the lesions was observed. A histopathological analysis was performed with skin fragments of lesions and with the spleen of animals treated with different treatments (emulgel, AmB 3% emulgel and AmB 3% plus OA 5% emulgel). It was observed that when subjected to treatment with AmB 3% emulgel during the study period using both formulations, with enhancer and without enhancer, ulcerative lesions regress gradually or even complete cure. The quantification of the average number of parasites recovered from the inoculation site was made after the treatment in each group and the differences were considered significant. The treatment with AmB 3% and OA 5% emulgel had the best in vivo therapeutic response, showing good prospects for cutaneous leishmaniasis therapy as an alternative therapy.

Role of nanotechnology in epigenetic reprogramming

With the recent advances in regenerative medicine, nanotechnology has created a niche for itself as a promising avenue in this field. Innumerable studies have been carried out by researchers using virus-based methodologies for the purpose of epigenetic reprogramming. Although this method is ostensibly safe, nonetheless, they are tagged with the risk of viral genome integration into the host genome or insertional mutagenesis. Transient transfection by the use of nanocarriers is the best way to overcome these problems. This review focuses on some of the significant works carried out by researchers utilizing nanocarrier systems that have shown promising results and thus created a landmark in the epigenetic reprogramming.