Intracellular accumulation and immunological response of NIR-II polymeric nanoparticles

Polymeric nanoparticles (NPs) are extremely promising for theranostic applications. However, their interest depends largely on their interactions with immune system, including the capacity to activate inflammation after their capture by macrophages. In the present study, we generated monodisperse poly(ethyl methacrylate) (PEMA) NPs loaded with hydrophobic photoluminescent gold nanoclusters (Au NCs) emitting in the NIR-II optical windows and studied their interaction in vitro with J774.1A macrophages. PEMA NPs showed an efficient time and dose dependent cellular uptake with up to 70 % of macrophages labelled in 24 h without detectable cell death. Interestingly, PEMA and Au-PEMA NPs induced an anti-inflammatory response and a strong down-regulation of nitric oxide level on lipopolysacharides (LPS) activated macrophages, but without influence on the levels of reactive oxygen species (ROS). These polymeric NPs may thus present a potential interest for the treatment of inflammatory diseases.

Chronic inflammation in psoriasis promotes visceral adipose tissue association with lipid-rich necrotic core through atherogenic myeloid score

Background/Introduction

Psoriasis is a chronic inflammatory condition associated with adipose dysfunction and high-risk coronary artery disease features, including non-calcified coronary burden (NCB) and lipid-rich necrotic core (LRNC). Visceral adipose tissue (VAT) is a metabolically-active depot that secretes inflammatory and proatherogenic factors, and is associated with increased NCB. Additionally, an atherogenic myeloid score (AMS) comprised of classical monocytes, low-density granulocytes, and platelets was shown to associate with psoriasis severity and NCB.

Purpose

To investigate the relationship between VAT and high-risk plaque features and test whether this relationship was potentially mediated by myeloid cells.

Methods

A cohort of 131 psoriasis patients were included in this study. Atherogenic myeloid score components were calculated using complete blood count data (platelets) and by flow cytometry (monocytes, LDGs). Coronary NCB and LRNC were quantified using QAngio and vascuCAP respectively. VAT was defined as intra-abdominal fat and was quantified using an automated contouring software with abdominal CT scans. Statistical analyses were performed using STATA 12.

Results

The cohort was middle-aged 50 (42–61) (median (IQR)), and predominantly male (61%). High VAT vs low VAT groups differed significantly in their NCB ((0.910±0.279) vs (1.431±0.517)); p<0.001), (mean ± SD). After adjustment for cardiovascular risk factors, VAT associated with the atherogenic myeloid score (β=0.221, p=0.044), with LRNC (β=0.128, p=0.047), and atherogenic myeloid score associated with LRNC (β=0.161, p=0.003). The relationship of VAT to LRNC was partially mediated by atherogenic myeloid score (25.14%, p=0.029) (Figure 1).

Conclusions

VAT associated with LRNC, and this relationship was partially mediated by the atherogenic myeloid score. These findings suggest that bioactive VAT may impart risk on coronary artery disease in part through myeloid cells.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Heart, Lung, and Blood Institute Intramural Research Program in Bethesda, Maryland Figure 1. Log-transformed atherogenic myeloid score partially mediates the relationship between VAT and log-transformed LRNC. Adjusted by Framingham Risk Score, PASI score, biologic therapy, statin therapy, type 2 diabetes, hyperlipidemia, and subcutaneous adipose tissue volume. Red arrow: represents indirect effect; Beta: standard regression coefficient.

Tuning the Immunostimulation Properties of Cationic Lipid Nanocarriers for Nucleic Acid Delivery

Nonviral systems, such as lipid nanoparticles, have emerged as reliable methods to enable nucleic acid intracellular delivery. The use of cationic lipids in various formulations of lipid nanoparticles enables the formation of complexes with nucleic acid cargo and facilitates their uptake by target cells. However, due to their small size and highly charged nature, these nanocarrier systems can interact in vivo with antigen-presenting cells (APCs), such as dendritic cells (DCs) and macrophages. As this might prove to be a safety concern for developing therapies based on lipid nanocarriers, we sought to understand how they could affect the physiology of APCs. In the present study, we investigate the cellular and metabolic response of primary macrophages or DCs exposed to the neutral or cationic variant of the same lipid nanoparticle formulation. We demonstrate that macrophages are the cells affected most significantly and that the cationic nanocarrier has a substantial impact on their physiology, depending on the positive surface charge. Our study provides a first model explaining the impact of charged lipid materials on immune cells and demonstrates that the primary adverse effects observed can be prevented by fine-tuning the load of nucleic acid cargo. Finally, we bring rationale to calibrate the nucleic acid load of cationic lipid nanocarriers depending on whether immunostimulation is desirable with the intended therapeutic application, for instance, gene delivery or messenger RNA vaccines.

Therapeutic siRNAs Targeting the JAK/STAT Signalling Pathway in Inflammatory Bowel Diseases

BACKGROUND AND AIMS

Inflammatory bowel diseases are highly debilitating conditions that require constant monitoring and life-long medication. Current treatments are focused on systemic administration of immunomodulatory drugs, but they have a broad range of undesirable side-effects. RNA interference is a highly specific endogenous mechanism that regulates the expression of the gene at the transcript level, which can be repurposed using exogenous short interfering RNA [siRNA] to repress expression of the target gene. While siRNA therapeutics can offer an alternative to existing therapies, with a high specificity critical for chronically administrated drugs, evidence of their potency compared to chemical kinase inhibitors used in clinics is still lacking in alleviating an adverse inflammatory response.

METHODS

We provide a framework to select highly specific siRNA, with a focus on two kinases strongly involved in pro-inflammatory diseases, namely JAK1 and JAK3. Using western-blot, real-time quantitative PCR and large-scale analysis, we assessed the specificity profile of these siRNA drugs and compared their efficacy to the most recent and promising kinase inhibitors for Janus kinases [Jakinibs], tofacitinib and filgotinib.

RESULTS

siRNA drugs can reach higher efficiency and selectivity at lower doses [5 pM vs 1 µM] than Jakinibs. Moreover, JAK silencing lasted up to 11 days, even with 6 h pulse transfection.

CONCLUSIONS

The siRNA-based drugs developed hold the potential to develop more potent therapeutics for chronic inflammatory diseases.

Hybrid multimodal contrast agent for multiscale in vivo investigation of neuroinflammation

Neuroinflammation is a process common to several brain pathologies. Despites its medical relevance, it still remains poorly understood; there is therefore a need to develop new in vivo preclinical imaging strategies to monitor inflammatory processes longitudinally. We here present the development of a hybrid imaging nanoprobe named NP3, that was specifically designed to get internalized by phagocytic cells and imaged in vivo with MRI and bi-photon microscopy. NP3 is composed of a 16 nm core of gadolinium fluoride (GdF3), coated with bisphosphonate polyethylene glycol (PEG) and functionalized with a Lemke-type fluorophore. It has a hydrodynamic diameter of 28 ± 8 nm and a zeta potential of -42 ± 6 mV. The MR relaxivity ratio at 7 T is r1/r2 = 20; therefore, NP3 is well suited as a T2/T2* contrast agent. In vitro cytotoxicity assessments performed on four human cell lines revealed no toxic effects of NP3. In addition, NP3 is internalized by macrophages in vitro without inducing inflammation or cytotoxicity. In vivo, uptake of NP3 has been observed in the spleen and the liver. NP3 has a prolonged vascular remanence, which is an advantage for macrophage uptake in vivo. The proof-of-concept that NP3 may be used as a contrast agent targeting phagocytic cells is provided in an animal model of ischemic stroke in transgenic CX3CR1-GFP/+ mice using three complementary imaging modalities: MRI, intravital two-photon microscopy and phase contrast imaging with synchrotron X-rays. In summary, NP3 is a promising preclinical tool for the multiscale and multimodal investigation of neuroinflammation.

Impact of Gold Nanoparticles on the Functions of Macrophages and Dendritic Cells

Gold nanoparticles (AuNPs) have demonstrated outstanding performance in many biomedical applications. Their safety is recognised; however, their effects on the immune system remain ill defined. Antigen-presenting cells (APCs) are immune cells specialised in sensing external stimulus and in capturing exogenous materials then delivering signals for the immune responses. We used primary macrophages (Ms) and dendritic cells (DCs) of mice as an APC model. Whereas AuNPs did not alter significantly Ms and DCs functions, the exposure to AuNPs affected differently Ms and DCs in their responses to subsequent stimulations. The secretion of inflammatory molecules like cytokines (IL-6, TNF-α), chemokine (MCP-1), and reactive oxygen species (ROS) were altered differently in Ms and DCs. Furthermore, the metabolic activity of Ms was affected with the increase of mitochondrial respiration and glycolysis, while only a minor effect was seen on DCs. Antigen presentation to T cells increased when DCs were exposed to AuNPs leading to stronger Th1, Th2, and Th17 responses. In conclusion, our data provide new insights into the complexity of the effects of AuNPs on the immune system. Although AuNPs may be considered as devoid of significant effect, they may induce discrete modifications on some functions that can differ among the immune cells.

Synthesis and use of an amphiphilic dendrimer for siRNA delivery into primary immune cells

Using siRNAs to genetically manipulate immune cells is important to both basic immunological studies and therapeutic applications. However, siRNA delivery is challenging because primary immune cells are often sensitive to the delivery materials and generate immune responses. We have recently developed an amphiphilic dendrimer that is able to deliver siRNA to a variety of cells, including primary immune cells. We provide here a protocol for the synthesis of this dendrimer, as well as siRNA delivery to immune cells such as primary T and B cells, natural killer cells, macrophages, and primary microglia. The dendrimer synthesis entails straightforward click coupling followed by an amidation reaction, and the siRNA delivery protocol requires simple mixing of the siRNA and dendrimer in buffer, with subsequent application to the primary immune cells to achieve effective and functional siRNA delivery. This dendrimer-mediated siRNA delivery largely outperforms the standard electroporation technique, opening a new avenue for functional and therapeutic studies of the immune system. The whole protocol encompasses the dendrimer synthesis, which takes 10 days; the primary immune cell preparation, which takes 3-10 d, depending on the tissue source and cell type; the dendrimer-mediated siRNA delivery; and subsequent functional assays, which take an additional 3-6 d.

Hepatitis C as a potential cause of IgA nephropathy

This is a case report of a 16-year-old boy presenting with a history of oliguria and anasarca. Workup revealed marked proteinuria to the tune of 8 g/day. He was subsequently found to be hepatitis C positive. Genotype was hepatitis C virus type 6. Renal biopsy revealed mesangioproliferative glomerulonephritis with IgA deposits consistent with IgA nephropathy (IgAN). Initiation of oral ribavirin and pegylated interferon caused a marked reduction in proteinuria after 8 weeks of treatment. It was postulated that hepatitis C manifested as IgAN. This case report thus sheds light on the possibility of an association between hepatitis C and IgAN.

A complete task analysis to measure the workload associated with operating an agricultural sprayer equipped with a navigation device

The objective of this study was to perform a complete task analysis to measure the workload associated with operating an agricultural sprayer equipped with a navigation device. The task analysis included a written questionnaire and subsequent observation of sprayer operators. The questionnaire revealed that the lightbar was the most important source of guidance information (as opposed to relying on guidance information from external field cues). Observation consisted of recording eye-glance behaviour and heart rate variability while operators were spraying in a field setting. The eye-glance data suggest that external cues are more important than the lightbar for providing the necessary navigation information. Thus, the questionnaire and observation data contradict each other. Based on heart rate variability, operators who used a lightbar navigation device experienced more mental workload than operators who used an auto-steer navigation device.

Training of final year MBBS students in neonatal resuscitation

Sixty final year MBBS students were trained in the art of neonatal resuscitation based on the 'NALS' course material. The students scored 11.6 +/- 3.02 in the pretest and 17.85 +/- 4.42 (out of 20) in the post-test. The trainees felt that the programme was extremely useful. Majority of them said that the course content was optimum with appropriate use of teaching-learning media. It is recommended that this training may be imparted to all the undergraduate students at the entry of final year MBBS course before their labor room posting so that they can have effective reinforcement of the training.

Changing pattern of antimicrobial utilization in an Indian teaching hospital

A study was conducted at Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India, on the pattern of antimicrobial utilization in hospitalized patients. A retrospective study was conducted during a one-month period between January 18 to February 17, 1987. The data were analyzed according to modified Kunin's criteria. The results were compared with a similar study conducted a decade ago. The study revealed a marked increase in the use of antimicrobial agents (from 19.9% to 56.1%). A more appropriate use of antimicrobial agents was observed (from 66.8% to 79.5%). A significant increase in their appropriate use for therapeutic purpose (50% to 88.2%), but not for prophylaxis (79.05% to 71.18%) was seen. The study revealed a marked increase in the use of antimicrobial agents during the last decade resulting in the emergence of nosocomial infections of resistant strains of organisms.

Chelation reactions of adenine

Chelation reactions of the antimitotic drug, 6-amino-purine (adenine; abbr. ADN) with the metal ions: Be(II), Al(III), Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Pb(II), and UO2(II) have been investigated in aqueous solution at 30° using Bjerrum-Calvin pH titration technique. The formation constants have been determined at various ionic concentrations, and have been extrapolated to zero ionic strength to get the thermodynamic values of the constants.

Avidity of folic acid for carcinogenic metal ions aluminium(3), chromium(3), beryllium(II), lead(II) and uranium(VI)

Stepwise formation constants of folic acid, N-[p-[[ (2-amino-4-hydroxy-6-pteridyl) methyl] amino] benzyl] glutamic acid, with the carcinogenic metal ions, aluminium (III), chromium (III), beryllium (II), lead (II) and uranium (VI) have been determined at 30 °C, and at various ionic strengths, viz. 0.01 ᴍ, 0.05 ᴍ, 0.10 ᴍ, maintained by potassium nitrate solution. The formation of the chelate is evident from the shift between the (i) ligand and (ii) ligand and metal titration curves. From the values for the stepwise protonation constants and metal-ligand stability constants at various ionic strengths, thermodynamic formation constants were evaluated by extrapolation to zero ionic concentration. Logarithms of the overall thermodynamic stability constants (log Kμ=0) are: 20.40 for H-; 15.15 for Al-; 10.10 for Cr-; 9.35 for Be-; 6.50 for Pb-; 9.00 for U-chelates. Corresponding free energy changes (ΔF0) are -28.47, -21.14, -14.09, -13.05, -9.07, -12.56 K · Cal · mol-1 respectively