Recent advances in lipid nanoparticles for delivery of nucleic acid,mRNA, and gene editing-based therapeutics

Lipid nanoparticles (LNPs) are becoming popular as a means of delivering therapeutics, including those based on nucleic acids and mRNA. The mRNA-based coronavirus disease 2019 vaccines are perfect examples to highlight the role played by drug delivery systems in advancing human health. The fundamentals of LNPs for the delivery of nucleic acid- and mRNA-based therapeutics, are well established. Thus, future research on LNPs will focus on addressing the following: expanding the scope of drug delivery to different constituents of the human body, expanding the number of diseases that can be targeted, and studying the change in the pharmacokinetics of LNPs under physiological and pathological conditions. This review article provides an overview of recent advances aimed at expanding the application of LNPs, focusing on the pharmacokinetics and advantages of LNPs. In addition, analytical techniques, library construction and screening, rational design, active targeting, and applicability to gene editing therapy have also been discussed.     

外泌体作为靶向治疗载体的研究进展

外泌体是来源于细胞内膜的纳米级的囊泡，包含有核酸、蛋白和脂质等生命物质，作为一种细胞间交流的机制，在生命活动中发挥着重要作用。相对于脂质体载体，外泌体更稳定，生物相容性好，免疫原性低，而且可以渗透生物屏障，例如血脑屏障、胎盘屏障等。重点介绍外泌体载体靶向性的基础、外泌体载体装载负荷的方法及外泌体载体目前的应用进展和前景。     

靶向超声造影剂在干细胞移植中的研究进展

近年来,干细胞移植技术在心肌梗死的治疗中应用越来越广泛。实验研究发现,靶向超声微泡技术能够有效增强心肌梗死区域局部血管的通透性、提高该区域内相关细胞因子的表达效率、增加梗死区新生血管的形成,从而促进干细胞靶向归巢、改善心功能,提高干细胞移植的成功率。因此,本文通过整理总结相关资料,对将超声联合微泡技术应用于干细胞移植治疗急性心肌梗死过程中的研究进展做一综述。     

The transduction pattern of IL‐12‐encoding lentiviral vectors shapes the immunological outcome

In situ modification of antigen‐presenting cells garnered interest in cancer immunotherapy. Therefore, we developed APC‐targeted lentiviral vectors (LVs). Unexpectedly, these LVs were inferior vaccines to broad tropism LVs. Since IL‐12 is a potent mediator of antitumor immunity, we evaluated whether this proinflammatory cytokine could enhance antitumor immunity of an APC‐targeted LV‐based vaccine. Therefore, we compared subcutaneous administration of broad tropism LVs (VSV‐G‐LV) with APC‐targeted LVs (DC2.1‐LV)‐encoding enhanced GFP and ovalbumin, or IL‐12 and ovalbumin in mice. We show that codelivery of IL‐12 by VSV‐G‐LVs or DC2.1‐LVs augments CD4⁺ or CD8⁺ T‐cell proliferation, respectively. Furthermore, we demonstrate that codelivery of IL‐12 enhances the CD4⁺ T_H1 profile irrespective of its delivery mode, while an increase in cytotoxic and therapeutic CD8⁺ T cells was only induced upon VSV‐G‐LV injection. While codelivery of IL‐12 by DC2.1‐LVs did not enhance CD8⁺ T‐cell performance, it increased expression of inhibitory checkpoint markers Lag3, Tim3, and PD‐1. Finally, the discrepancy between CD4⁺ T‐cell stimulation with and without functional CD8⁺ T‐cell stimulation by VSV‐G‐ and DC2.1‐LVs is partly explained by the observation that IL‐12 relieves CD8⁺ T cells from CD4⁺ T‐cell help, implying that a T_H1 profile is of minor importance for antitumor immunotherapy if IL‐12 is exogenously delivered.     

An orally administrated nucleotide-delivery vehicle targeting colonic macrophages for the treatment of inflammatory bowel disease

Tumor necrosis factor-alpha (TNF-α) plays a central role in the pathogenesis of inflammatory bowel disease (IBD). Anti-TNF-α therapies have shown protective effects against colitis, but an efficient tool for target suppression of its secretion - ideally via oral administration - remains in urgent demand. In the colon tissue, TNF-α is mainly secreted by the colonic macrophages. Here, we report an orally-administrated microspheric vehicle that can target the colonic macrophages and suppress the local expression of TNF-α for IBD treatment. This vehicle is formed by cationic konjac glucomannan (cKGM), phytagel and an antisense oligonucleotide against TNF-α. It was given to dextran sodium sulfate (DSS) colitic mice via gastric perfusion. The unique swelling properties of cKGM enabled the spontaneous release of cKGM& antisense nucleotide (ASO) nano-complex from the phytagel scaffold into the colon lumen, where the ASO was transferred into colonic macrophages via receptor-mediated phagocytosis. The treatment significantly decreased the local level of TNF-α and alleviated the symptoms of colitis in the mice. In summary, our study demonstrates a convenient, orally-administrated drug delivery system that effectively targets colonic macrophages for suppression of TNF-α expression. It may represent a promising therapeutic approach in the treatment of IBD.     

Being targeted: Young women's experience of being identified for a teenage pregnancy prevention programme

Research on the unintended consequences of targeting ‘high-risk’ young people for health interventions is limited. Using qualitative data from an evaluation of the Teens & Toddlers Pregnancy Prevention programme, we explored how young women experienced being identified as at risk for teenage pregnancy to understand the processes via which unintended consequences may occur. Schools' lack of transparency regarding the targeting strategy and criteria led to feelings of confusion and mistrust among some young women. Black and minority ethnic young women perceived that the assessment of their risk was based on stereotyping. Others felt their outgoing character was misinterpreted as signifying risk. To manage these imposed labels, stigma and reputational risks, young women responded to being targeted by adopting strategies, such as distancing, silence and refusal. To limit harmful consequences, programmes could involve prospective participants in determining their need for intervention or introduce programmes for young people at all levels of risk.     

False-Positive β-Galactosidase Staining in Osteoclasts by Endogenous Enzyme: Studies in Neonatal and Month-Old Wild-Type Mice

Escherichia coli β-galactosidase (β-gal), encoded by the lacZ gene, has become an essential tool in studies of gene expression and function in higher eukaryotes. lac-Z is widely used as a marker gene to detect expression of transgenes or Cre recombinase driven by tissue-specific promoters. The timing and location of promoter activity is easily visualized in whole embryos or specific tissues using the cleavable, chromogenic substrate, 5-bromo-4-chloro-3-indolyl-D-galactopyranoside (X-gal). The tissue specificity of promoters in transgenic constructs is routinely tested by using a promoter of choice to drive lacZ. Alternatively, the targeted expression of Cre recombinase to perform in vivo recombination of loxP sites can be visualized by β-gal staining in mice carrying a Cre-activated lacZ transgene, such as the ROSA26 strain. In the course of our investigations, we examined β-gal activity in bone tissue from genetically normal mice using standard detection methodology and found very high endogenous activity in bone-resorbing osteoclasts. This was true in frozen, paraffin, and glycol methacrylate sections. X-gal staining colocalized with the osteoclast marker, tartrate-resistant acid phosphatase (TRAP). β-gal activity was present in osteoclasts in long bones, in the mandible, and in both neonatal and more mature animals. We present this brief article as a caution to those testing genetic models of skeletal gene expression using β-gal as a marker gene.     

Antibody-based fusion proteins to target death receptors in cancer

Ideally, an immunotoxin should be inactive ‘en route’, acquire activity only after tumor cell surface binding and have no off-target effects towards normal cells. In this respect, antibody-based fusion proteins that exploit the tumor-selective pro-apoptotic death ligands sFasL and sTRAIL appear promising. Soluble FasL largely lacks receptor-activating potential, whereas sTRAIL is inactive towards normal cells. Fusion proteins in which an anti-tumor antibody fragment (scFv) is fused to sFasL or sTRAIL prove to be essentially inactive when soluble, while gaining potent anti-tumor activity after selective binding to a predefined tumor-associated cell surface antigen. Importantly, off-target binding by scFv:sTRAIL to normal cells showed no signs of toxicity. In this review, we highlight the rationale and perspectives of scFv:TRAIL/scFv:sFasL based fusion proteins for cancer therapy.     

Nanomedicine for acute respiratory distress syndrome: The latest application,targeting strategy,and rational design

Acute respiratory distress syndrome (ARDS) is characterized by the severe inflammation and destruction of the lung air–blood barrier, leading to irreversible and substantial respiratory function damage. Patients with coronavirus disease 2019 (COVID-19) have been encountered with a high risk of ARDS, underscoring the urgency for exploiting effective therapy. However, proper medications for ARDS are still lacking due to poor pharmacokinetics, non-specific side effects, inability to surmount pulmonary barrier, and inadequate management of heterogeneity. The increased lung permeability in the pathological environment of ARDS may contribute to nanoparticle-mediated passive targeting delivery. Nanomedicine has demonstrated unique advantages in solving the dilemma of ARDS drug therapy, which can address the shortcomings and limitations of traditional anti-inflammatory or antioxidant drug treatment. Through passive, active, or physicochemical targeting, nanocarriers can interact with lung epithelium/endothelium and inflammatory cells to reverse abnormal changes and restore homeostasis of the pulmonary environment, thereby showing good therapeutic activity and reduced toxicity. This article reviews the latest applications of nanomedicine in pre-clinical ARDS therapy, highlights the strategies for targeted treatment of lung inflammation, presents the innovative drug delivery systems, and provides inspiration for strengthening the therapeutic effect of nanomedicine-based treatment.     

Site-Specific Drug Targeting with Fluorouracil Microspheres

Abstract

The disposition of 5-fluorouracil following intra-arterial administration in albino rats, as a free drug suspension (control) or via magnetic albumin microspheres (treatment group) in normal saline, has been investigated. The rat tail was used as the target model wherein fluorouracil microspheres were injected into the ventral caudal artery. A magnetic field of 6000 G was directed toward a predetermined site on the tail. On analysis, it was observed that the magnetically responsive albumin microspheres of fluorouracil showed an increase in drug retention at the target site and liver. However, drug retention in the heart, kidney, and tissues in close proximity to the target site was considerably less. It was also observed that the amount of drug retained in nontarget sites (heart, kidney, and lungs) was less when fluorouracil was administered in the microsphere form rather than as a suspension. This results in low drug exposure of nontarget organs with the microsphere form, which would otherwise have exhibited toxicity effects.