Harnessing RNA Technology to Advance Therapeutic Vaccine Antigens against Chagas Disease

Chagas disease (CD) (American trypanosomiasis caused by Trypanosoma cruzi) is a parasitic disease endemic in 21 countries in South America, with increasing global spread. When administered late in the infection, the current antiparasitic drugs do not prevent the onset of cardiac illness leading to chronic Chagasic cardiomyopathy. Therefore, new therapeutic vaccines or immunotherapies are under development using multiple platforms. In this study, we assessed the feasibility of developing an mRNA-based therapeutic CD vaccine targeting two known T. cruzi vaccine antigens (Tc24─a flagellar antigen and ASP-2─an amastigote antigen). We present the mRNA engineering steps, preparation, and stability of the lipid nanoparticles and evaluation of their uptake by dendritic cells, as well as their biodistribution in c57BL/J mice. Furthermore, we assessed the immunogenicity and efficacy of two mRNA-based candidates as monovalent and bivalent vaccine strategies using an in vivo chronic mouse model of CD. Our results show several therapeutic benefits, including reductions in parasite burdens and cardiac inflammation, with each mRNA antigen, especially with the mRNA encoding Tc24, and Tc24 in combination with ASP-2. Therefore, our findings demonstrate the potential of mRNA-based vaccines as a therapeutic option for CD and highlight the opportunities for developing multivalent vaccines using this approach.

Vulnerability of terrestrial vertebrate food webs to anthropogenic threats in Europe

Vertebrate species worldwide are currently facing significant declines in many populations. Although we have gained substantial knowledge about the direct threats that affect individual species, these threats only represent a fraction of the broader vertebrate threat profile, which is also shaped by species interactions. For example, threats faced by prey species can jeopardize the survival of their predators due to food resource scarcity. Yet, indirect threats arising from species interactions have received limited investigation thus far. In this study, we investigate the indirect consequences of anthropogenic threats on biodiversity in the context of European vertebrate food webs. We integrated data on trophic interactions among over 800 terrestrial vertebrates, along with their associated human-induced threats. We quantified and mapped the vulnerability of various components of the food web, including species, interactions, and trophic groups to six major threats: pollution, agricultural intensification, climate change, direct exploitation, urbanization, and invasive alien species and diseases. Direct exploitation and agricultural intensification were two major threats for terrestrial vertebrate food webs: affecting 34% and 31% of species, respectively, they threaten 85% and 69% of interactions in Europe. By integrating network ecology with threat impact assessments, our study contributes to a better understanding of the magnitude of anthropogenic impacts on biodiversity.

Intramuscular but not nebulized administration of a mRNA vaccine against Rhodococcus equi stimulated humoral immune responses in neonatal foals

OBJECTIVE

Design and evaluate immune responses of neonatal foals to a mRNA vaccine expressing the virulence-associated protein A (VapA) of Rhodococcus equi.

ANIMALS

Cultured primary equine respiratory tract cells; Serum, bronchoalveolar lavage fluid (BALF), and peripheral blood mononuclear cells (PBMCs) from 30 healthy Quarter Horse foals.

METHODS

VapA expression was evaluated by western immunoblot in cultured equine bronchial cells transfected with 4 mRNA constructs encoding VapA. The mRNA construct with greatest expression was used to immunize foals at ages 2 and 21 days in 5 groups: (1) 300 μg nebulized mRNA (n = 6); (2) 600 μg nebulized mRNA (n = 4); (3) 300 μg mRNA administered intramuscularly (IM) (n = 5); (4) 300 μg VapA IM (positive controls; n = 6); or (5) nebulized water (negative controls; n = 6). Serum, BALF, and PBMCs were collected at ages 3, 22, and 35 days and tested for relative anti-VapA IgG1, IgG4/7, and IgA activities using ELISA and cell-mediated immunity by ELISpot.

RESULTS

As formulated, nebulized mRNA was not immunogenic. However, a significant increase in anti-VapA IgG4/7 activity (P < .05) was noted exclusively in foals immunized IM with VapA mRNA by age 35 days. The proportion of foals with anti-VapA IgG1 activity > 30% of positive control differed significantly (P = .0441) between negative controls (50%; 3/6), IM mRNA foals (100%; 5/5), and IM VapA (100%; 6/6) groups. Natural exposure to virulent R equi was immunogenic in some negative control foals.

CLINICAL RELEVANCE

Further evaluation of the immunogenicity and efficacy of IM mRNA encoding VapA in foals is warranted.

Increase of nesting habitat suitability for green turtles in a warming Mediterranean Sea

Climate change is reshaping global ecosystems at an unprecedented rate, with major impacts on biodiversity. Therefore, understanding how organisms can withstand change is key to identify priority conservation objectives. Marine ectotherms are being extremely impacted because their biology and phenology are directly related to temperature. Among these species, sea turtles are particularly problematic because they roam over both marine and terrestrial habitats throughout their life cycles. Focusing on green turtles (Chelonia mydas) in the Mediterranean Sea, we investigated the future potential changes of nesting grounds through time, assuming that marine turtles would shift their nesting locations. We modeled the current distribution of nesting grounds including both terrestrial and marine variables, and we projected the potential nesting distribution across the Mediterranean basin under alternative future greenhouse gas emission scenario (2000-2100). Our models show an increase in nesting probability in the western Mediterranean Sea, irrespective of the climate scenario we consider. Contrary to what is found in most global change studies, the worse the climate change scenario, the more suitable areas for green turtles will potentially increase. The most important predictors were anthropogenic variables, which negatively affect nesting probability, and sea surface temperature, positively linked to nesting probability, up to a maximum of 24-25 °C. The importance of the western Mediterranean beaches as potential nesting areas for sea turtles in the near future clearly call for a proactive conservation and management effort, focusing on monitoring actions (to document the potential range expansion) and threat detection.

Heterologous mRNA-protein vaccination with Tc24 induces a robust cellular immune response against Trypanosoma cruzi, characterized by an increased level of polyfunctional CD8+ T-cells

Tc24 is a Trypanosoma cruzi-derived flagellar protein that, when formulated with a TLR-4 agonist adjuvant, induces a balanced immune response in mice, elevating IgG2a antibody titers and IFN-γ levels. Furthermore, vaccination with the recombinant Tc24 protein can reduce parasite levels and improve survival during acute infection. Although some mRNA vaccines have been proven to elicit a stronger immune response than some protein vaccines, they have not been used against T. cruzi. This work evaluates the immunogenicity of a heterologous prime/boost vaccination regimen using protein and mRNA-based Tc24 vaccines. Mice (C57BL/6) were vaccinated twice subcutaneously, three weeks apart, with either the Tc24-C4 protein + glucopyranosyl A (GLA)-squalene emulsion, Tc24 mRNA Lipid Nanoparticles, or with heterologous protein/mRNA or mRNA/protein combinations, respectively. Two weeks after the last vaccination, mice were euthanized, spleens were collected to measure antigen-specific T-cell responses, and sera were collected to evaluate IgG titers and isotypes. Heterologous presentation of the Tc24 antigen generated antigen-specific polyfunctional CD8+ T cells, a balanced Th1/Th2/Th17 cytokine profile, and a balanced humoral response with increased serum IgG, IgG1 and IgG2c antibody responses. We conclude that heterologous vaccination using Tc24 mRNA to prime and Tc24-C4 protein to boost induces a broad and robust antigen-specific immune response that was equivalent or superior to two doses of a homologous protein vaccine, the homologous mRNA vaccine and the heterologous Tc24-C4 Protein/mRNA vaccine.

Reasons for the Sex Bias in Osteoarthritis Research: A Review of Preclinical Studies

Osteoarthritis (OA) is one of the most common degenerative diseases of articular cartilage. During OA, all the elements that contribute to the joint undergo physiological and structural changes that impair the joint function and cause joint pain and stiffness. OA can arise naturally, with the aging population witnessing an increase in diagnoses of this pathology, but the root causes of OA have yet to be identified, and increasing interest is arising towards investigating biological sex as a risk factor. Clinical studies show increased prevalence and worse clinical outcomes for female patients, yet most clinical and preclinical studies have disproportionately focused on male subjects. This review provides a critical overview of preclinical practices in the context of OA, highlighting the underlying need for taking biological sex as both a risk factor and an important component affecting treatment outcome. A unique insight into the possible reasons for female underrepresentation in preclinical studies is offered, including factors such as lack of specific guidelines requiring the analysis of sex as a biological variable (SABV), research-associated costs and animal handling, and wrongful application of the reduction principle. Additionally, a thorough investigation of sex-related variables is provided, stressing how each of them could add valuable information for the understanding of OA pathophysiology, as well as sex-dependent treatment strategies.

Immunomodulatory biomimetic nanoparticles target articular cartilage trauma after systemic administration

Post-traumatic osteoarthritis (PTOA) is one of the leading causes of disability in developed countries and accounts for 12% of all osteoarthritis cases in the United States. After trauma, inflammatory cells (macrophages amongst others) are quickly recruited within the inflamed synovium and infiltrate the joint space, initiating dysregulation of cartilage tissue homeostasis. Current therapeutic strategies are ineffective, and PTOA remains an open clinical challenge. Here, the targeting potential of liposome-based nanoparticles (NPs) is evaluated in a PTOA mouse model, during the acute phase of inflammation, in both sexes. NPs are composed of biomimetic phospholipids or functionalized with macrophage membrane proteins. Intravenous administration of NPs in the acute phase of PTOA and advanced in vivo imaging techniques reveal preferential accumulation of NPs within the injured joint for up to 7 days post injury, in comparison to controls. Finally, imaging mass cytometry uncovers an extraordinary immunomodulatory effect of NPs that are capable of decreasing the amount of immune cells infiltrating the joint and conditioning their phenotype. Thus, biomimetic NPs could be a powerful theranostic tool for PTOA as their accumulation in injury sites allows their identification and they have an intrinsic immunomodulatory effect.

Abstract 2709: Leukosome-based siRNA strategy for targeting ribosomal protein L39 (RPL39) in metaplastic breast cancer

Metaplastic breast cancer (MpBC) is a rare and highly aggressive subset accounting for &lt;5% of all BCs. Clinically, MpBCs exhibit the most dismal prognosis of all BC subtypes, with a median survival rate of 8 months in patients with metastatic disease. The main therapeutic option for MpBC remains standard chemotherapy, despite known resistance to most cytotoxic drugs. We recently reported that ~40% of MpBC patient samples display a gain-of-function oncogenic mutation (A14V) in ribosomal protein RPL39, which is responsible for treatment resistance, cancer stem cell self-renewal, and lung metastases. We also showed that high RPL39 levels were associated with worse survival in patients with MpBC. Collectively, these findings support the rationale of targeting this ubiquitous genetic marker in MpBC. This study was aimed to design an innovative targeted therapy against RPL39 by combining a small interfering RNA (siRNA) strategy (siRPL39) with biomimetic lipid nanoparticle (LNP) technology for in vivo delivery to MpBC cells. These LNPs referred to as “leukosomes” incorporate membrane proteins from circulating leukocytes to facilitate evasion of immune clearance, enhance tropism towards inflamed endothelium such as the tumor-associated one, and improve siRNA internalization into the tumor mass. For leukosomes synthesis, we adapted a microfluidic device to incorporate membrane proteins from leukocytes within lipid bilayers. This technique retained all the physical and biological features of leukosomes, combined with high siRNA loading efficiency. We evaluated in vitro uptake and efficacy of siRPL39-loaded leukosomes in MpBC cell lines. We found that fluorescently labeled siRPL39 was rapidly internalized by leukosomes into MpBC cells demonstrating efficient and uniform uptake without inducing cytotoxicity. Treatment of MpBC cells with siRPL39-loaded leukosomes exhibited significantly knockdown of RPL39 mRNA, further supporting that the observed siRNA internalization results in potent and specific gene silencing. Notably, siRPL39-loaded leukosomes inhibited in vitro cell proliferation as compared with control siRNA leukosomes, indicating a key role of RPL39 in MpBC growth. Next, we sought to evaluate functional gene silencing of siRPL39-loaded leukosomes in vivo. We established MpBC patient-derived xenografts (PDXs) in the mammary fat pad of humanized NSG mice. We revealed that leukosomes formulation enables siRPL39 accumulation and functional gene silencing in MpBC tumors after local administration, without causing overt toxicity. Overall, our findings highlight RPL39 as a novel therapeutic target in MpBC and provide proof of principle for the development of leukosome-based siRNA drugs to improve delivery to cancer cells. Ongoing studies are directed to evaluate biodistribution, in vivo silencing and therapeutic effects of siRPL39-leukosomes after systemic administration.

Citation Format: Maria Florencia Chervo, Chiara Mancino, Federica Giordano, Tejaswini P. Reddy, Wei Qian, Jianying Zhou, Liliana Guzman-Rojas, Roberto R. Rosato, Francesca Taraballi, Jenny C. Chang. Leukosome-based siRNA strategy for targeting ribosomal protein L39 (RPL39) in metaplastic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2709.

Electrospun electroconductive constructs of aligned fibers for cardiac tissue engineering

Myocardial infarction remains the leading cause of death in the western world. Since the heart has limited regenerative capabilities, several cardiac tissue engineering (CTE) strategies have been proposed to repair the damaged myocardium. A novel electrospun construct with aligned and electroconductive fibers combining gelatin, poly(lactic-co-glycolic) acid and polypyrrole that may serve as a cardiac patch is presented. Constructs were characterized for fiber alignment, surface wettability, shrinkage and swelling behavior, porosity, degradation rate, mechanical properties, and electrical properties. Cell-biomaterial interactions were studied using three different types of cells, Neonatal Rat Ventricular Myocytes (NRVM), human lung fibroblasts (MRC-5) and induced pluripotent stem cells (iPSCs). All cell types showed good viability and unique organization on construct surfaces depending on their phenotype. Finally, we assessed the maturation status of NRVMs after 14 days by confocal images and qRT-PCR. Overall evidence supports a proof-of-concept that this novel biomaterial construct could be a good candidate patch for CTE applications.

Mimicking cardiac tissue complexity through physical cues: A review on cardiac tissue engineering approaches

Cardiovascular diseases are the number one killer in the world.^1,2 Currently, there are no clinical treatments to regenerate damaged cardiac tissue, leaving patients to develop further life-threatening cardiac complications. Cardiac tissue has multiple functional demands including vascularization, contraction, and conduction that require many synergic components to properly work. Most of these functions are a direct result of the cardiac tissue structure and composition, and, for this reason, tissue engineering strongly proposed to develop substitute engineered heart tissues (EHTs). EHTs usually have combined pluripotent stem cells and supporting scaffolds with the final aim to repair or replace the damaged native tissue. However, as simple as this idea is, indeed, it resulted, after many attempts in the field, to be very challenging. Without design complexity, EHTs remain unable to mature fully and integrate into surrounding heart tissue resulting in minimal in vivo effects.³ Lately, there has been a growing body of evidence that a complex, multifunctional approach through implementing scaffold designs, cellularization, and molecular release appears to be essential in the development of a functional cardiac EHTs.^4-6 This review covers the advancements in EHTs developments focusing on how to integrate contraction, conduction, and vascularization mimics and how combinations have resulted in improved designs thus warranting further investigation to develop a clinically applicable treatment.

Reversal of long-standing iron deficiency anaemia after eradication of Helicobacter pylori infection

Helicobacter pylori has been proposed as a major determinant in multiple gastric disorders. We describe the case of a young adult with a long-standing medical history of sideropenic anaemia and of oral iron consumption dependence with a chronic superficial H. pylori-positive gastritis. All other causes of sideropenic anaemia were carefully excluded. Histology showed a peculiar pattern of non-active H. pylori-positive gastritis. The bacterium was a non-VacA-producing strain. The first attempt at eradication caused a reduction in bacterial load and led to a partial normalization of haematologic variables without improving the ferritin level. A successful second course of eradication therapy completely reversed the anaemia and restored the iron deposit, which persisted at the 29-month follow-up. H. pylori infection can be involved in unexplained cases of iron deficiency anaemia in adults, and its cure can normalize the haematologic picture.

Lipoprotein (a) levels in end-stage renal failure and renal transplantation

Some previous studies have documented an increase in lipoprotein (a) [Lp(a)] levels in renal diseases. Here, we report data in subjects with end-stage renal failure treated with hemodialysis (HD) or with continuous ambulatory peritoneal dialysis (CAPD) and in renal transplant recipients (RTR), compared with a group of normolipidemic controls (C). Lp(a) levels were significantly increased in HD and CAPD patients in comparison with C, while they were only slightly increased in RTR. Both HD and CAPD patients showed Lp(a) levels higher than in RTR, but no difference was found between the subjects of the two dialysis procedures. The prevalence of Lp(a) levels > 25 mg/dl was significantly higher in HD and CAPD patients, but not in RTR, in comparison with C. Moreover, Lp(a) levels did not change after HD. When patients were divided according to their fasting lipid levels in normolipidemics and hyperlipoproteinemics, no difference was found for Lp(a) levels in any group. Mechanisms underlying the increase in Lp(a) levels in these patients are not known. It is possible to suggest an active role of the kidney in the Lp(a) metabolism or that uremic plasma contains some factors affecting Lp(a) metabolism.

[Anti-islet cell antibodies in insulin-dependent diabetics. Preliminary study]

Anti-islet cell cytoplasm antibodies (ICA) were noted in the serum of insulin-dependent diabetics, but not in subjects with insulin-independent forms. These antibodies seem to represent an immunological marker for two forms of the disease, one in which ICA appears shortly after onset and later disappears, and another ("autoimmune") form in which ICA is detectable for long periods and persists along with other signs of alteration of the immune system.