Gene therapy progress and prospects: hydrodynamic gene delivery

Functionalized hydrogels as smart gene delivery systems to treat musculoskeletal disorders

Despite critical advances in regenerative medicine, the generation of definitive, reliable treatments for musculoskeletal diseases remains challenging. Gene therapy based on the delivery of therapeutic genetic sequences has strong value to offer effective, durable options to decisively manage such disorders. Furthermore, scaffold-mediated gene therapy provides powerful alternatives to overcome hurdles associated with classical gene therapy, allowing for the spatiotemporal delivery of candidate genes to sites of injury. Among the many scaffolds for musculoskeletal research, hydrogels raised increasing attention in addition to other potent systems (solid, hybrid scaffolds) due to their versatility and competence as drug and cell carriers in tissue engineering and wound dressing. Attractive functionalities of hydrogels for musculoskeletal therapy include their injectability, stimuli-responsiveness, self-healing, and nanocomposition that may further allow to upgrade of them as "intelligently" efficient and mechanically strong platforms, rather than as just inert vehicles. Such functionalized hydrogels may also be tuned to successfully transfer therapeutic genes in a minimally invasive manner in order to protect their cargos and allow for their long-term effects. In light of such features, this review focuses on functionalized hydrogels and demonstrates their competence for the treatment of musculoskeletal disorders using gene therapy procedures, from gene therapy principles to hydrogel functionalization methods and applications of hydrogel-mediated gene therapy for musculoskeletal disorders, while remaining challenges are being discussed in the perspective of translation in patients. STATEMENT OF SIGNIFICANCE: Despite advances in regenerative medicine, the generation of definitive, reliable treatments for musculoskeletal diseases remains challenging. Gene therapy has strong value in offering effective, durable options to decisively manage such disorders. Scaffold-mediated gene therapy provides powerful alternatives to overcome hurdles associated with classical gene therapy. Among many scaffolds for musculoskeletal research, hydrogels raised increasing attention. Functionalities including injectability, stimuli-responsiveness, and self-healing, tune them as "intelligently" efficient and mechanically strong platforms, rather than as just inert vehicles. This review introduces functionalized hydrogels for musculoskeletal disorder treatment using gene therapy procedures, from gene therapy principles to functionalized hydrogels and applications of hydrogel-mediated gene therapy for musculoskeletal disorders, while remaining challenges are discussed from the perspective of translation in patients.

HDI-STARR-seq: Condition-specific enhancer discovery in mouse liver in vivo

Background

STARR-seq and other massively-parallel reporter assays are widely used to discover functional enhancers in transfected cell models, which can be confounded by plasmid vector-induced type-I interferon immune responses and lack the multicellular environment and endogenous chromatin state of complex mammalian tissues.

Results

Here, we describe HDI-STARR-seq, which combines STARR-seq plasmid library delivery to the liver, by hydrodynamic tail vein injection (HDI), with reporter RNA transcriptional initiation driven by a minimal Albumin promoter, which we show is essential for mouse liver STARR-seq enhancer activity assayed 7 days after HDI. Importantly, little or no vector-induced innate type-I interferon responses were observed. Comparisons of HDI-STARR-seq activity between male and female mouse livers and in livers from males treated with an activating ligand of the transcription factor CAR (Nr1i3) identified many condition-dependent enhancers linked to condition-specific gene expression. Further, thousands of active liver enhancers were identified using a high complexity STARR-seq library comprised of ~ 50,000 genomic regions released by DNase-I digestion of mouse liver nuclei. When compared to stringently inactive library sequences, the active enhancer sequences identified were highly enriched for liver open chromatin regions with activating histone marks (H3K27ac, H3K4me1, H3K4me3), were significantly closer to gene transcriptional start sites, and were significantly depleted of repressive (H3K27me3, H3K9me3) and transcribed region histone marks (H3K36me3).

Conclusions

HDI-STARR-seq offers substantial improvements over current methodologies for large scale, functional profiling of enhancers, including condition-dependent enhancers, in liver tissue in vivo, and can be adapted to characterize enhancer activities in a variety of species and tissues by selecting suitable tissue- and species-specific promoter sequences.

Use of Intravoxel Incoherent Motion Diffusion-Weighted Imaging to Assess Mesenchymal Stromal Cells Promoting Liver Regeneration in a Rat Model

RATIONALE AND OBJECTIVES

Mesenchymal stem cells (MSCs) have the potential to promote liver regeneration, but the process is unclear. This study aims to explore the therapeutic effects and dynamic processes of MSCs in liver regeneration through intravoxel incoherent motion (IVIM) imaging.

ANIMAL MODEL

70 adult Sprague-Dawley rats were randomly divided into either the control or MSC group (n = 35/group). All rats received a partial hepatectomy (PH) with the left lateral and middle lobes removed. Each group was divided into seven subgroups: pre-PH and 1, 2, 3, 5, 7, and 14 days post-PH (n = 5 rats/subgroup). Magnetic resonance imaging (MRI) was performed before obtaining pathological specimens at each time point on postoperative days 1, 2, 3, 5, 7, and 14. The MRI parameters for the pure diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (PF) were calculated. Correlation analysis was conducted for the biochemical markers (alanine transaminase [ALT], aspartate transaminase [AST], and total bilirubin [TBIL]), histopathological findings (hepatocyte size and Ki-67 proliferation index), liver volume (LV) and liver regeneration rate (LLR).

RESULTS

Liver D, D* , and PF differed significantly between the control and MSC groups at all time points (all P < 0.05). After PH, the D increased, then decreased, and the D* and PF decreased, then increased in both groups. The hepatocyte Ki-67 proliferation index of the MSC group was lower on day 2 post-PH, but higher on days 3 and 5 post-PH than that of the control group. Starting from day 3 post-PH, both the LV and LLR in the MSC group were greater than those in the control group (all P < 0.05). Hepatocytes were larger in the MSC group than in the control group on days 2 and 7 post-PH. In the MSC group, the D, D* , and PF were correlated with the AST levels, Ki-67 index and hepatocyte size (|r|=0.35-0.71; P < 0.05). In the control group, the D and D* were correlated with ALT levels, AST levels, Ki-67 index, LLR, LV, and hepatocyte size (|r|=0.34-0.95; P < 0.05).

CONCLUSION

Bone marrow MSC therapy can promote hepatocyte hypertrophy and prolong liver proliferation post-PH. IVIM parameters allow non-invasively evaluating the efficacy of MSCs in promoting LR.

HDI-STARR-seq: Condition-specific enhancer discovery in mouse liver in vivo

STARR-seq and other massively-parallel reporter assays are widely used to discover functional enhancers in transfected cell models, which can be confounded by plasmid vector-induced type-I interferon immune responses and lack the multicellular environment and endogenous chromatin state of complex mammalian tissues. Here, we describe HDI-STARR-seq, which combines STARR-seq plasmid library delivery to the liver, by hydrodynamic tail vein injection (HDI), with reporter RNA transcriptional initiation driven by a minimal Albumin promoter, which we show is essential for mouse liver STARR-seq enhancer activity assayed 7 days after HDI. Importantly, little or no vector-induced innate type-I interferon responses were observed. Comparisons of HDI-STARR-seq activity between male and female mouse livers and in livers from males treated with an activating ligand of the transcription factor CAR (Nr1i3) identified many condition-dependent enhancers linked to condition-specific gene expression. Further, thousands of active liver enhancers were identified using a high complexity STARR-seq library comprised of ~50,000 genomic regions released by DNase-I digestion of mouse liver nuclei. When compared to stringently inactive library sequences, the active enhancer sequences identified were highly enriched for liver open chromatin regions with activating histone marks (H3K27ac, H3K4me1, H3K4me3), were significantly closer to gene transcriptional start sites, and were significantly depleted of repressive (H3K27me3, H3K9me3) and transcribed region histone marks (H3K36me3). HDI-STARR-seq offers substantial improvements over current methodologies for large scale, functional profiling of enhancers, including condition-dependent enhancers, in liver tissue in vivo, and can be adapted to characterize enhancer activities in a variety of species and tissues by selecting suitable tissue- and species-specific promoter sequences.

Hyaluronic acid-functionalized lipoplexes and polyplexes as emerging nanocarriers for receptor-targeted cancer therapy

Cancer is an intricate disease that develops as a response to a combination of hereditary and environmental risk factors, which then result in a variety of changes to the genome. The cluster of differentiation (CD44) is a type of transmembrane glycoprotein that serves as a potential biomarker for cancer stem cells (CSC) and viable targets for therapeutic intervention in the context of cancer therapy. Hyaluronic acid (HA) is a linear polysaccharide that exhibits a notable affinity for the CD44 receptor. This characteristic renders it a promising candidate for therapeutic interventions aimed at selectively targeting CD44-positive cancer cells. Treating cancer via non-viral vector-based gene delivery has changed the notion of curing illness through the incorporation of therapeutic genes into the organism. The objective of this review is to provide an overview of various hyaluronic acid-modified lipoplexes and polyplexes as potential drug delivery methods for specific forms of cancer by effectively targeting CD44.

Comprehensive in-silico analysis of deleterious SNPs in APOC2 and APOA5 and their differential expression in cancer and cardiovascular diseases conditions

Genetic variations in APOC2 and APOA5 genes involve activating lipoprotein lipase (LPL), responsible for the hydrolysis of triglycerides (TG) in blood and whose impaired functions affect the TG metabolism and are associated with metabolic diseases. In this study, we investigate the biological significance of genetic variations at the DNA sequence and structural level using various computational tools. Subsequently, 8 (APOC2) and 17 (APOA5) non-synonymous SNPs (nsSNPs) were identified as high-confidence deleterious SNPs based on the effects of the mutations on protein conservation, stability, and solvent accessibility. Furthermore, based on our docking results, the interaction of native and mutant forms of the corresponding proteins with LPL depicts differences in root mean square deviation (RMSD), and binding affinities suggest that these mutations may affect their function. Furthermore, in vivo, and in vitro studies have shown that differential expression of these genes in disease conditions due to the influence of nsSNPs abundance may be associated with promoting the development of cancer and cardiovascular diseases. Preliminary screening using computational methods can be a helpful start in understanding the effects of mutations in APOC2 and APOA5 on lipid metabolism; however, further wet-lab experiments would further strengthen the conclusions drawn from the computational study.

Enhancing the expression of a key mitochondrial enzyme at the inception of ischemia-reperfusion injury can boost recovery and halt the progression of acute kidney injury

Hydrodynamic fluid delivery has shown promise in influencing renal function in disease models. This technique provided pre-conditioned protection in acute injury models by upregulating the mitochondrial adaptation, while hydrodynamic injections of saline alone have improved microvascular perfusion. Accordingly, hydrodynamic mitochondrial gene delivery was applied to investigate the ability to halt progressive or persistent renal function impairment following episodes of ischemia-reperfusion injuries known to induce acute kidney injury (AKI). The rate of transgene expression was approximately 33% and 30% in rats with prerenal AKI that received treatments 1 (T1hr) and 24 (T24hr) hours after the injury was established, respectively. The resulting mitochondrial adaptation via exogenous IDH2 (isocitrate dehydrogenase 2 (NADP+) and mitochondrial) significantly blunted the effects of injury within 24 h of administration: decreased serum creatinine (≈60%, p < 0.05 at T1hr; ≈50%, p < 0.05 at T24hr) and blood urea nitrogen (≈50%, p < 0.05 at T1hr; ≈35%, p < 0.05 at T24hr) levels, and increased urine output (≈40%, p < 0.05 at T1hr; ≈26%, p < 0.05 at T24hr) and mitochondrial membrane potential, Δψm, (≈ by a factor of 13, p < 0.001 at T1hr; ≈ by a factor of 11, p < 0.001 at T24hr), despite elevated histology injury score (26%, p < 0.05 at T1hr; 47%, p < 0.05 at T24hr). Therefore, this study identifies an approach that can boost recovery and halt the progression of AKI at its inception.

Early Subcellular Hepatocellular Alterations in Mice Post Hydrodynamic Transfection: An Explorative Study

Hydrodynamic transfection (HT) or hydrodynamic tail vein injection (HTVi) is among the leading technique that is used to deliver plasmid genes mainly into the liver of live mice or rats. The DNA constructs are composed of coupled plasmids, while one contains the gene of interest that stably integrate into the hepatocyte genome with help of the other consisting sleeping beauty transposase system. The rapid injection of a large volume of DNA-solution through the tail vein induces an acute cardiac congestion that refluxed into the liver, mainly in acinus zone 3, also found through our EM study. Although, HT mediated hydrodynamic force can permeabilizes the fenestrated sinusoidal endothelium of liver, but the mechanism of plasmid incorporation into the hepatocytes remains unclear. Therefore, in the present study, we have hydrodynamically injected 2 mL volume of empty plasmid (transposon vector) or saline solution (control) into the tail vein of anesthetized C57BL/6J/129Sv mice. Liver tissue was resected at different time points from two animal group conditions, i.e., one time point per animal (1, 5, 10-20, 60 min or 24 and 48 hrs after HT) or multiple time points per animal (0, 1, 2, 5, 10, 20 min) and quickly fixed with buffered 4% osmium tetroxide. The tissues fed with only saline solution was also resected and fixed in the similar way. EM evaluation from the liver ultrathin sections reveals that swiftly after 1 min, the hepatocytes near to the central venule in the acinus zone 3 shows cytoplasmic membrane-bound vesicles. Such vesicles increased in both numbers and size to vacuoles and precisely often found in the proximity to the nucleus. Further, EM affirm these vacuoles are also optically empty and do not contain any electron dense material. Although, some of the other hepatocytes reveals sign of cell damage including swollen mitochondria, dilated endoplasmic reticulum, Golgi apparatus and disrupted plasma membrane, but most of the hepatocytes appeared normal. The ultrastructural findings in the mice injected with empty vector or saline injected control mice were similar. Therefore, we have interpreted the vacuole formation as nonspecific endocytosis without specific interactions at the plasma membrane.

Microfluidics in drug delivery: review of methods and applications

Microfluidics technology has emerged as a promising methodology for the fabrication of a wide variety of advanced drug delivery systems. Owing to its ability for accurate handling and processing of small quantities of fluidics as well as immense control over physicochemical properties of fabricated micro and nanoparticles (NPs), microfluidic technology has significantly improved the pharmacokinetics and pharmacodynamics of drugs. This emerging technology has offered numerous advantages over the conventional drug delivery methods for fabricating of a variety of micro and nanocarriers for poorly soluble drugs. In addition, a microfluidic system can be designed for targeted drug delivery aiming to increase the local bioavailability of drugs. This review spots the light on the recent advances made in the area of microfluidics including various methods of fabrication of drug carriers, their characterization, and unique features. Furthermore, applications of microfluidic technology for the robust fabrication and development of drug delivery systems, the existing challenges associated with conventional fabrication methodologies as well as the proposed solutions offered by microfluidic technology have been discussed in details.HighlightsMicrofluidic technology has revolutionized fabrication of tunable micro and nanocarriers.Microfluidic platforms offer several advantages over the conventional fabrication methods.Microfluidic devices hold great promise in controlling the physicochemical features of fabricated drug carriers.Micro and nanocarriers with controllable release kinetics and site-targeting efficiency can be fabricated.Drug carriers fabricated by microfluidic technology exhibited improved pharmacokinetic and pharmacodynamic profiles.

Therapeutic effect of multiple functional minicircle vector encoding anti-CD25/IL-10/CXCR3 in allograft rejection model

BACKGROUND/AIMS

We previously proposed minicircle vector technology as the potential platform for the development and production of new biologics. In this study, we have designed a novel target molecule for the treatment of allograft rejection and evaluated its feasibility as the therapeutic agent in this disease using the minicircle vector system.

METHODS

We engineered vectors to carry cassette sequences for anti-CD25, interleukin-10 (IL-10), and C-X-C motif chemokine receptor 3 (CXCR3) fusion protein, and then isolated minicircle vectors from the parent vectors. We verified the substantial production of anti-CD25/IL-10/CXCR3 fusion protein from minicircles and their duration in HEK293T cells and mice models. We also evaluated whether minicircle-derived anti-CD25/IL-10/CXCR3 has therapeutic effects in a skin allograft in mice model.

RESULTS

We confirmed the production of anti-CD25/IL-10/CXCR3 from minicircle by its significant availability in cells transfected with the minicircle and in its conditioned media. After a single injection of minicircle by hydrodynamic injection via mouse tail vein, luminescence or red fluorescence was maintained until 40 days in the liver tissue, suggesting the production of anti-CD25/IL-10/CXCR3 protein from minicircles via protein synthesis machinery in the liver. Mice treated with the minicircle encoding anti-CD25/IL-10/CXCR3 showed prolonged skin allograft survival times accompanied by improved immunologic regulation e.g., reduction of the lymphocyte population of Th1, Th2, and Th17 and an induction of regulatory T cells.

CONCLUSION

These findings implied that self-generated anti-CD25/IL-10/CXCR3 protein drug by minicircle technology is functionally active and relevant for reducing allograft rejection. The minicircle vector system may be useful for developing new biological drugs, avoiding manufacturing or practical problems.

Pre-clinical non-viral vectors exploited for in vivo CRISPR/Cas9 gene editing: an overview

Clustered regulatory interspaced short palindromic repeats or CRISPR/Cas9 has emerged as a potent and versatile tool for efficient genome editing. This technology has been exploited for several applications including disease modelling, cell therapy, diagnosis, and treatment of many diseases including cancer. The in vivo application of CRISPR/Cas9 is hindered by poor stability, pharmacokinetic profile, and the limited ability of the CRISPR payloads to cross biological barriers. Although viral vectors have been implemented as delivery tools for efficient in vivo gene editing, their application is associated with high immunogenicity and toxicity, limiting their clinical translation. Hence, there is a need to explore new delivery methods that can guarantee safe and efficient delivery of the CRISPR/Cas9 components to target cells. In this review, we first provide a brief history and principles of nuclease-mediated gene editing, we then focus on the different CRISPR/Cas9 formats outlining their potentials and limitations. Finally, we discuss the alternative non-viral delivery strategies currently adopted for in vivo CRISPR/Cas9 gene editing.

Delivery of non-viral naked DNA vectors to liver in small weaned pigs by hydrodynamic retrograde intrabiliary injection

Hepatic gene therapy by delivering non-integrating therapeutic vectors in newborns remains challenging due to the risk of dilution and loss of efficacy in the growing liver. Previously we reported on hepatocyte transfection in piglets by intraportal injection of naked DNA vectors. Here, we established delivery of naked DNA vectors to target periportal hepatocytes in weaned pigs by hydrodynamic retrograde intrabiliary injection (HRII). The surgical procedure involved laparotomy and transient isolation of the liver. For vector delivery, a catheter was placed within the common bile duct by enterotomy. Under optimal conditions, no histological abnormalities were observed in liver tissue upon pressurized injections. The transfection of hepatocytes in all tested liver samples was observed with vectors expressing luciferase from a liver-specific promoter. However, vector copy number and luciferase expression were low compared to hydrodynamic intraportal injection. A 10-fold higher number of vector genomes and luciferase expression was observed in pigs using a non-integrating naked DNA vector with the potential for replication. In summary, the HRII application was less efficient (i.e., lower luciferase activity and vector copy numbers) than the intraportal delivery method but was significantly less distressful for the piglets and has the potential for injection (or re-injection) of vector DNA by endoscopic retrograde cholangiopancreatography.

Bezafibrate induces hypothyroidism in a patient with resistance to thyroid hormone β due to a G347R variant

OBJECTIVE

A unique clinical course was observed in a patient with resistance to thyroid hormone β (RTHβ) caused by a variant of the THRB gene leading to the replacement of glycine with arginine in codon 347 (p.G347R). He presented with the syndrome of inappropriate secretion of thyrotropin (TSH) (free T4 [fT4]: 32.43 pmol/L, TSH: 4.67 mIU/L), but slowly developed progressive hypothyroidism (fT4: 8.37 pmol/L, TSH: 100.90 mIU/L) that resolved after suspending bezafibrate (BZ) treatment (fT4: 32.18 pmol/L, TSH: 7.14 mIU/L). This study clinically and experimentally evaluated this interesting phenomenon.

METHODS

A retrospective cohort analysis of non-RTHβ patients was performed at Kyoto University Hospital. Data before BZ treatment were compared to the first data after treatment. Using reporter assays of iodothyronine deiodinases (DIO1, DIO2, DIO3) in HEK293T cells, we performed functional analyses of mutant thyroid hormone receptor β with p.G347R (G347R TRβ). Mice with G347R TRβ were generated by hydrodynamic gene delivery.

RESULTS

In non-RTHβ patients (n = 7), BZ treatment did not change serum free T3 and TSH but significantly increased fT4 (p = .008). BZ administration increased DIO3 reporter activity in the context of G347R TRβ, whereas did not change DIO1 and DIO2 reporter activity. In the livers of mice with G347R TRβ, BZ administration increased reverse T3 content, which corresponded to an increase in Dio3 messenger RNA.

CONCLUSIONS

While hypothyroidism associated with BZ treatment did not occur in non-RTHβ patients, it was observed in a patient with RTHβ due to the p.G347R variant. Liver DIO3 upregulation might involve this hypothyroidism.

Conventional type 1 dendritic cells protect against age-related adipose tissue dysfunction and obesity

Conventional dendritic cells (cDCs) scan and integrate environmental cues in almost every tissue, including exogenous metabolic signals. While cDCs are critical in maintaining immune balance, their role in preserving energy homeostasis is unclear. Here, we showed that Batf3-deficient mice lacking conventional type 1 DCs (cDC1s) had increased body weight and adiposity during aging. This led to impaired energy expenditure and glucose tolerance, insulin resistance, dyslipidemia, and liver steatosis. cDC1 deficiency caused adipose tissue inflammation that was preceded by a paucity of NK1.1⁺ invariant NKT (iNKT) cells. Accordingly, among antigen-presenting cells, cDC1s exhibited notable induction of IFN-γ production by iNKT cells, which plays a metabolically protective role in lean adipose tissue. Flt3L treatment, which expands the dendritic cell (DC) compartment, mitigated diet-induced obesity and hyperlipidemia in a Batf3-dependent manner. This effect was partially mediated by NK1.1⁺ cells. These results reveal a new critical role for the cDC1-iNKT cell axis in the regulation of adipose tissue homeostasis.

Endoscopic-mediated, biliary hydrodynamic injection mediating clinically relevant levels of gene delivery in pig liver

BACKGROUND AND AIMS

Gene therapy could provide curative therapies to many inherited monogenic liver diseases. Clinical trials have largely focused on adeno-associated viruses (AAVs) for liver gene delivery. These vectors, however, are limited by small packaging size, capsid immune responses, and inability to redose. As an alternative, nonviral, hydrodynamic injection through vascular routes can successfully deliver plasmid DNA (pDNA) into mouse liver but has achieved limited success in large animal models.

METHODS

We explored hydrodynamic delivery of pDNA through the biliary system into the liver of pigs using ERCP and a power injector to supply hydrodynamic force. Human factor IX (hFIX), deficient in hemophilia B, was used as a model gene therapy.

RESULTS

Biliary hydrodynamic injection was well tolerated without significant changes in vital signs, liver enzymes, hematology, or histology. No off-target pDNA delivery to other organs was detected by polymerase chain reaction. Immunohistochemistry revealed that 50.19% of the liver stained positive for hFIX after hydrodynamic injection at 5.5 mg pDNA, with every hepatic lobule in all liver lobes demonstrating hFIX expression. hFIX-positive hepatocytes were concentrated around the central vein, radiating outward across all 3 metabolic zones. Biliary hydrodynamic injection in pigs resulted in significantly higher transfection efficiency than mouse vascular hydrodynamic injection at matched pDNA per liver weight dose (32.7%-51.9% vs 18.9%, P < .0001).

CONCLUSIONS

Biliary hydrodynamic injection using ERCP can achieve higher transfection efficiency into hepatocytes compared with AAVs at magnitudes of less cost in a clinically relevant human-sized large animal. This technology may serve as a platform for gene therapy of human liver diseases.

Nanomedicine for Gene Delivery and Drug Repurposing in the Treatment of Muscular Dystrophies

Muscular Dystrophies (MDs) are a group of rare inherited genetic muscular pathologies encompassing a variety of clinical phenotypes, gene mutations and mechanisms of disease. MDs undergo progressive skeletal muscle degeneration causing severe health problems that lead to poor life quality, disability and premature death. There are no available therapies to counteract the causes of these diseases and conventional treatments are administered only to mitigate symptoms. Recent understanding on the pathogenetic mechanisms allowed the development of novel therapeutic strategies based on gene therapy, genome editing CRISPR/Cas9 and drug repurposing approaches. Despite the therapeutic potential of these treatments, once the actives are administered, their instability, susceptibility to degradation and toxicity limit their applications. In this frame, the design of delivery strategies based on nanomedicines holds great promise for MD treatments. This review focuses on nanomedicine approaches able to encapsulate therapeutic agents such as small chemical molecules and oligonucleotides to target the most common MDs such as Duchenne Muscular Dystrophy and the Myotonic Dystrophies. The challenge related to in vitro and in vivo testing of nanosystems in appropriate animal models is also addressed. Finally, the most promising nanomedicine-based strategies are highlighted and a critical view in future developments of nanomedicine for neuromuscular diseases is provided.

Interleukin-39 exacerbates concanavalin A-induced liver injury

BACKGROUND

Interleukin (IL)-39 is a novel member of IL-12 family and has been reported to play a pro-inflammatory role in lupus-like mice, but its function in concanavalin A (ConA)-induced liver injury is currently unclear.

MATERIALS AND METHODS

In this study, we investigated the effects of IL-39 expression in a mouse model of ConA induced-hepatitis. We first showed that delivery of plasmid DNA encoding mouse IL-39 using the hydrodynamic tail vein injection method increased IL-39 mRNA and protein levels in the liver. We then administrated mice with IL-39 plasmid before ConA injection and measured serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, inflammatory infiltration, and hepatocyte necrosis in the liver. Additionally, we further explored the potential mechanism of IL-39 in ConA-induced liver injury by measuring several inflammatory mediators.

RESULTS

We found that ectopic IL-39 expression promoted the ConA-induced increase in serum ALT and AST levels, inflammatory infiltration, and hepatocyte necrosis in the liver. We also observed that IL-39 plasmid administration significantly increased serum and liver interferon-γ, tumor necrosis factor-α, and IL-17A levels, but did not affect serum and liver IL-10 levels in ConA-induced hepatitis.

CONCLUSION

Our results suggest that IL-39 can exacerbate ConA-induced hepatitis and may be a therapeutic target in inflammatory liver disease.

Delivery Approaches for Therapeutic Genome Editing and Challenges

Impressive therapeutic advances have been possible through the advent of zinc-finger nucleases and transcription activator-like effector nucleases. However, discovery of the more efficient and highly tailorable clustered regularly interspaced short palindromic repeats (CRISPR) and associated proteins (Cas9) has provided unprecedented gene-editing capabilities for treatment of various inherited and acquired diseases. Despite recent clinical trials, a major barrier for therapeutic gene editing is the absence of safe and effective methods for local and systemic delivery of gene-editing reagents. In this review, we elaborate on the challenges and provide practical considerations for improving gene editing. Specifically, we highlight issues associated with delivery of gene-editing tools into clinically relevant cells.

Somatic Liver Knockout (SLiK): A Quick and Efficient Way to Generate Liver-Specific Knockout Mice Using Multiplex CRISPR/Cas9 Gene Editing

Somatic liver knockout (SLiK) is a method developed to rapidly generate a liver-specific knockout of one or several genes. This technique combines the strengths of CRISPR/Cas9 gene editing and hydrodynamic tail-vein injection, a simple in vivo method for transfection of hepatocytes, to harness the powerful selection pressure of tyrosinemic livers to replace host hepatocytes with any desired gene deletion. In this protocol, we will describe sgRNA design and cloning, hydrodynamic tail-vein injection of targeting constructs, and screening and validation methods for efficient in vivo gene editing. © 2020 by John Wiley & Sons, Inc. Support Protocol 1: sgRNA design Support Protocol 2: sgRNA construction: daisy chaining multiple sgRNAs Basic Protocol: Delivery of DNA by hydrodynamic tail-vein injection and liver repopulation of edited hepatocytes Support Protocol 3: Validation of CRISPR/Cas9 cutting in vivo.

C-Type Natriuretic Peptide Restores Growth Impairment Under Enzyme Replacement in Mice With Mucopolysaccharidosis VII

Growth impairment in mucopolysaccharidoses (MPSs) is an unresolved issue as it is resistant to enzyme replacement therapy (ERT) and growth hormone therapy. C-type natriuretic peptide (CNP) is a promising agent that has growth-promoting effects. Here we investigate the effects of CNP on growth impairment of MPSs using Gusbmps-2J mice, a model for MPS type VII, with combination therapy of CNP and ERT by hydrodynamic gene delivery. Although monotherapies were not sufficient to restore short statures of treated mice, combination therapy resulted in successful restoration. The synergistic effects of CNP and ERT were not only observed in skeletal growth but also in growth plates. ERT reduced cell swelling in the resting zone and increased cell number by accelerating proliferation or inhibiting apoptosis. CNP thickened the proliferative and hypertrophic zones. Regarding changes in the bone, ERT restored bone sclerosis through decreased bone formation and increased bone resorption, and CNP did not adversely affect this process. In addition, improvement of joint deformation by ERT was suggested by analyses of joint spaces and articular cartilage. CNP additively provided restoration of the short stature of MPS VII mice in combination with ERT, which improved abnormalities of growth plates and bone metabolism.

Host cell in vivo production of the synthetic drug anti-CD25/IL-10 using minicircle vector

Synthetic biologic drugs are highly successful for induction therapy in transplantation, but the development of novel biologics is limited because of the high cost of synthesis and purification. In this study, we developed a novel strategy for the production of synthetic protein drugs in vivo by the host itself. We utilized minicircle (MC) technology, which can robustly express a target molecule and secrete it from cells, as an indirect method to produce a protein of interest in vivo. We designed an MC vector containing the sequences of basiliximab (anti-CD25 mAb) and IL-10. We verified the substantial production of the anti-CD25/IL-10 protein from the MC in vitro and in vivo. The therapeutic effect of MC-derived anti-CD25/IL-10 was evaluated in a skin allograft mouse model by single intravenous infusion. Mice treated with the MC encoding anti-CD25/IL-10 exhibited prolonged skin allograft survival times accompanied by improved histologic changes and immunologic regulation. These findings indicate that the anti-CD25/IL-10 protein drug obtained by MC technology is functionally active and relevant for reducing allograft rejection. This self-reproducible strategy for synthetic protein drugs using MCs is a promising tool for transplantation.-Lim, S. W., Shin, Y. J., Luo, K., Quan, Y., Ko, E. J., Chung, B. H., Yang, C. W. Host cell in vivo production of the synthetic drug anti-CD25/IL-10 using minicircle vector.

Non-Viral Vectors for Gene Delivery

Introduction:

Gene therapy has emerged out as a promising therapeutic pave for the treatment of genetic and acquired diseases. Gene transfection into target cells using naked DNA is a simple and safe approach which has been further improved by combining vectors or gene carriers. Both viral and non-viral approaches have achieved a milestone to establish this technique, but non-viral approaches have attained a significant attention because of their favourable properties like less immunotoxicity and biosafety, easy to produce with versatile surface modifications, etc. Literature is rich in evidences which revealed that undoubtedly, non–viral vectors have acquired a unique place in gene therapy but still there are number of challenges which are to be overcome to increase their effectiveness and prove them ideal gene vectors.

Conclusion:

To date, tissue specific expression, long lasting gene expression system, enhanced gene transfection efficiency has been achieved with improvement in delivery methods using non-viral vectors. This review mainly summarizes the various physical and chemical methods for gene transfer in vitro and in vivo.

Interleukin-35 expression protects against cigarette smoke-induced lung inflammation in mice

Cigarette smoke (CS) is a very important cause of pulmonary inflammatory diseases. Interleukin (IL)-35 is a novel anti-inflammatory cytokine but its role in CS-mediated lung inflammation remains unclear. In the present study, we examined the effect of IL-35 expression on CS-induced lung inflammation in mice. A plasmid DNA expressing IL-35 was injected into mice via a hydrodynamic-based gene delivery that were subsequently exposed to CS three times a day for 5 days. We found that IL-35 expression inhibited pulmonary inflammatory infiltration, lung tissue lesions, mucus secretion, and myeloperoxidase activity in CS-treated mice. Moreover, IL-35 expression decreased the production of IL-1β, tumor necrosis factor-α, IL-6, and IL-17, but increased the level of IL-10 in bronchoalveolar lavage fluids and lung tissues from CS-challenged mice. These results suggest that in vivo expression of IL-35 can protect against CS-induced lung inflammation and may be a therapeutic target in CS-related pulmonary diseases.

Ex Vivo Major Histocompatibility Complex I Knockdown Prolongs Rejection-free Allograft Survival

Supplemental Digital Content is available in the text.

Background:

Widespread application of vascularized composite allotransplantation (VCA) is currently limited by the required lifelong systemic immunosuppression and its associated morbidity and mortality. This study evaluated the efficacy of ex vivo (after procurement but before transplantation) engineering of allografts using small interfering RNA to knockdown major histocompatibility complex I (MHC-I) and prolong rejection-free survival.

Methods:

Endothelial cells (ECs) were transfected with small interfering RNA targeted against MHC-I (siMHC-I) for all in vitro experiments. MHC-I surface expression and knockdown duration were evaluated using quantitative polymerase chain reaction (qPCR) and flow cytometry. After stimulating Lewis recipient cytotoxic lymphocytes (CTL) with allogeneic controls or siMHC-I–silenced ECs, lymphocyte proliferation, CTL-mediated and natural killer–mediated EC lysis were measured. Using an established VCA rat model, allografts were perfused ex vivo with siMHC-I before transplantation. Allografts were analyzed for MHC-I expression and clinical/histologic evidence of rejection.

Results:

Treatment with siMHC-I resulted in 80% knockdown of mRNA and 87% reduction in cell surface expression for up to 7 days in vitro (P < 0.05). Treatment of ECs with siMHC-I reduced lymphocyte proliferation and CTL-mediated cytotoxicity (77% and 50%, respectively, P < 0.01), without increasing natural killer–mediated cytotoxicity (P = 0.66). In a rat VCA model, ex vivo perfusion with siMHC-I reduced expression in all tissue compartments by at least 50% (P < 0.05). Knockdown prolonged rejection-free survival by 60% compared with nonsense-treated controls (P < 0.05).

Conclusions:

Ex vivo siMHC-I engineering can effectively modify allografts and significantly prolong rejection-free allograft survival. This novel approach may help reduce future systemic immunosuppression requirements in VCA recipients.

Intracellular Delivery by Membrane Disruption: Mechanisms, Strategies, and Concepts

Intracellular delivery is a key step in biological research and has enabled decades of biomedical discoveries. It is also becoming increasingly important in industrial and medical applications ranging from biomanufacture to cell-based therapies. Here, we review techniques for membrane disruption-based intracellular delivery from 1911 until the present. These methods achieve rapid, direct, and universal delivery of almost any cargo molecule or material that can be dispersed in solution. We start by covering the motivations for intracellular delivery and the challenges associated with the different cargo types-small molecules, proteins/peptides, nucleic acids, synthetic nanomaterials, and large cargo. The review then presents a broad comparison of delivery strategies followed by an analysis of membrane disruption mechanisms and the biology of the cell response. We cover mechanical, electrical, thermal, optical, and chemical strategies of membrane disruption with a particular emphasis on their applications and challenges to implementation. Throughout, we highlight specific mechanisms of membrane disruption and suggest areas in need of further experimentation. We hope the concepts discussed in our review inspire scientists and engineers with further ideas to improve intracellular delivery.

Prime-and-Trap Malaria Vaccination To Generate Protective CD8+ Liver-Resident Memory T Cells

Tissue-resident memory CD8⁺ T (Trm) cells in the liver are critical for long-term protection against pre-erythrocytic Plasmodium infection. Such protection can usually be induced with three to five doses of i.v. administered radiation-attenuated sporozoites (RAS). To simplify and accelerate vaccination, we tested a DNA vaccine designed to induce potent T cell responses against the SYVPSAEQI epitope of Plasmodium yoelii circumsporozoite protein. In a heterologous "prime-and-trap" regimen, priming using gene gun-administered DNA and boosting with one dose of RAS attracted expanding Ag-specific CD8⁺ T cell populations to the liver, where they became Trm cells. Vaccinated in this manner, BALB/c mice were completely protected against challenge, an outcome not reliably achieved following one dose of RAS or following DNA-only vaccination. This study demonstrates that the combination of CD8⁺ T cell priming by DNA and boosting with liver-homing RAS enhances formation of a completely protective liver Trm cell response and suggests novel approaches for enhancing T cell-based pre-erythrocytic malaria vaccines.

Zinc alpha2 glycoprotein protects against obesity-induced hepatic steatosis

BACKGROUND/AIM

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis, impaired insulin sensitivity, and chronic low-grade inflammation. Our previous studies indicated that zinc alpha2 glycoprotein (ZAG) alleviates palmitate (PA)-induced intracellular lipid accumulation in hepatocytes. This study is to further characterize the roles of ZAG on the development of hepatic steatosis, insulin resistance (IR), and inflammation.

METHODS

ZAG protein levels in the livers of NAFLD patients, high-fat diet (HFD)-induced or genetically (ob/ob) induced obese mice, and in PA-treated hepatocytes were determined by western blotting. C57BL/6J mice injected with an adenovirus expressing ZAG were fed HFD for indicated time to induce hepatic steatosis, IR, and inflammation, and then biomedical, histological, and metabolic analyses were conducted to identify pathologic alterations in these mice. The molecular mechanisms underlying ZAG-regulated hepatic steatosis were further explored and verified in mice and hepatocytes.

RESULTS

ZAG expression was decreased in NAFLD patient liver biopsy samples, obese mice livers, and PA-treated hepatocytes. Simultaneously, ZAG overexpression alleviated intracellular lipid accumulation via upregulating adiponectin and lipolytic genes (FXR, PPARα, etc.) while downregulating lipogenic genes (SREBP-1c, LXR, etc.) in obese mice as well as in cultured hepatocytes. ZAG improved insulin sensitivity and glucose tolerance via activation of IRS/AKT signaling. Moreover, ZAG significantly inhibited NF-ĸB/JNK signaling and thus resulting in suppression of obesity-associated inflammatory response in hepatocytes.

CONCLUSIONS

Our results revealed that ZAG could protect against NAFLD by ameliorating hepatic steatosis, IR, and inflammation.

Microfluidic Devices for Drug Delivery Systems and Drug Screening

Microfluidic devices present unique advantages for the development of efficient drug carrier particles, cell-free protein synthesis systems, and rapid techniques for direct drug screening. Compared to bulk methods, by efficiently controlling the geometries of the fabricated chip and the flow rates of multiphase fluids, microfluidic technology enables the generation of highly stable, uniform, monodispersed particles with higher encapsulation efficiency. Since the existing preclinical models are inefficient drug screens for predicting clinical outcomes, microfluidic platforms might offer a more rapid and cost-effective alternative. Compared to 2D cell culture systems and in vivo animal models, microfluidic 3D platforms mimic the in vivo cell systems in a simple, inexpensive manner, which allows high throughput and multiplexed drug screening at the cell, organ, and whole-body levels. In this review, the generation of appropriate drug or gene carriers including different particle types using different configurations of microfluidic devices is highlighted. Additionally, this paper discusses the emergence of fabricated microfluidic cell-free protein synthesis systems for potential use at point of care as well as cell-, organ-, and human-on-a-chip models as smart, sensitive, and reproducible platforms, allowing the investigation of the effects of drugs under conditions imitating the biological system.

Hepatitis B Virus-Specific CD8+ T Cells Maintain Functional Exhaustion after Antigen Reexposure in an Acute Activation Immune Environment

Chronic hepatitis B virus (HBV) infection is characterized by the presence of functionally exhausted HBV-specific CD8+ T cells. To characterize the possible residual effector ability of these cells, we reexposed CD8+ T cells from chronically HBV replicating mice to HBV antigens in an acute activation immune environment. We found that after transfer into naive mice, exhausted CD8+ T cells reexpanded in a comparable magnitude as naive CD8+ T cells in response to acute HBV infection; however, their proliferation intensity was significantly lower than that of CD8+ T cells from acute-resolving HBV replicating mice (AR mice). The differentiation phenotypes driven by acute HBV replication of donor exhausted and naive CD8+ T cells were similar, but were different from those of their counterparts from AR mice. Nevertheless, exhausted CD8+ T cells maintained less activated phenotype, an absence of effector cytokine production and poor antiviral function after HBV reexposure in an acute activation immune environment. We thus conclude that exhausted CD8+ T cells undergo a stable form of dysfunctional differentiation during chronic HBV replication and switching immune environment alone is not sufficient for the antiviral functional reconstitution of these cells.

Efficacy and Safety of Pancreas-Targeted Hydrodynamic Gene Delivery in Rats

Development of an effective, safe, and convenient method for gene delivery to the pancreas is a critical step toward gene therapy for pancreatic diseases. Therefore, we tested the possibility of applying the principle of hydrodynamic gene delivery for successful gene transfer to pancreas using rats as a model. The established procedure involves the insertion of a catheter into the superior mesenteric vein with temporary blood flow occlusion at the portal vein and hydrodynamic injection of DNA solution. We demonstrated that our procedure achieved efficient pancreas-specific gene expression that was 2,000-fold higher than that seen in the pancreas after the systemic hydrodynamic gene delivery. In addition, the level of gene expression achieved in the pancreas by the pancreas-specific gene delivery was comparable to the level in the liver achieved by a liver-specific hydrodynamic gene delivery. The optimal level of reporter gene expression in the pancreas requires an injection volume equivalent to 2.0% body weight with flow rate of 1 mL/s and plasmid DNA concentration at 5 μg/mL. With the exception of transient expansion of intercellular spaces and elevation of serum amylase levels, which recovered within 3 days, no permanent tissue damage was observed. These results suggest that pancreas-targeted hydrodynamic gene delivery is an effective and safe method for gene delivery to the pancreas and clinically applicable.

Hydrodynamic IL10 Gene Transfer in Human Colon: Results from an "EX VIVO" Study with Potential Clinical Application in Crohn's Disease

BACKGROUND

The aim of this work is to evaluate the efficacy of hydrodynamic venous IL10 gene delivery to "ex vivo" human colon segments and to determine its potential interest in Crohn's disease treatment.

METHODS

Twenty human colon segments were obtained from surgical resections. Hydrodynamic transfection through the main vein of the pedicle with 50 mL of hIL10 plasmid (20 μg/mL) solution was performed on 13 of them. Tissue sections were cultured and DNA, RNA, and protein copies were determined after 1, 2, and 4 days. Data obtained were compared with 6 nontransfected specimens. Finally, 1 specimen was injected with gold nanoparticles, and their distribution was examined under electron microscope.

RESULTS

IL10 DNA levels were higher in treated tissues than in controls (P < 0.001), decreasing along time. The amount of hIL10 RNA was significantly increased in treated tissues when compared with controls (P = 0.001). The indexes of protein IL10 translation in treated groups were much higher (P < 0.001) than the basal production. The protein expression was higher in transfected tissue (10-50-fold, with respect to control tissue); this difference being established during the first hours and maintained during, at least, 4 days. With electron microscopy, we hardly observed large (15 nm) gold nanoparticles within the tissue, always in the submucosa. However, multiple small (4 nm) nanoparticles were observed within the cytoplasm of enterocytes in mucosa.

CONCLUSIONS

Hydrodynamic procedure efficiently delivers the IL10 gene to the human colon, achieving levels of tissue protein expression high enough to mediate pharmacological effects with interest in controlling immune response in patients with Crohn's disease.

Improved siRNA delivery efficiency via solvent-induced condensation of micellar nanoparticles

Efficient delivery of short interfering RNA (siRNA) remains one of the primary challenges of RNA interference therapy. Polyethylene glycol (PEG)ylated polycationic carriers have been widely used for the condensation of DNA and RNA molecules into complex-core micelles. The PEG corona of such nanoparticles can significantly improve their colloidal stability in serum, but PEGylation of the carriers also reduces their condensation capacity, hindering the generation of micellar particles with sufficient complex stability. This presents a particularly significant challenge for packaging siRNA into complex micelles, as it has a much smaller size and more rigid chain structure than DNA plasmids. Here, we report a new method to enhance the condensation of siRNA with PEGylated linear polyethylenimine using organic solvent and to prepare smaller siRNA nanoparticles with a more extended PEG corona and consequently higher stability. As a proof of principle, we have demonstrated the improved gene knockdown efficiency resulting from the reduced siRNA micelle size in mice livers following intravenous administration.

Virus-Inspired Self-Assembled Nanofibers with Aggregation-Induced Emission for Highly Efficient and Visible Gene Delivery

High-efficiency gene transfer and suitably low cytotoxicity are the main goals of gene transfection systems based on nonviral vectors. In addition, it is desirable to track the gene transfer process in order to observe and explain the mechanism. Herein, inspired by viral structures that are optimized for gene delivery, we designed a small-molecule gene vector (TR4) with aggregation-induced emission properties by capping a peptide containing four arginine residues with tetraphenylethene (TPE) and a lipophilic tail. This novel vector can self-assemble with plasmid DNA to form nanofibers in solution with low cytotoxicity, high stability, and high transfection efficiency. pDNA@TR4 complexes were able to transfect a variety of different cell lines, including stem cells. The self-assembly process induces bright fluorescence from TPE, which makes the nanofibers visible by confocal laser scanning microscopy (CLSM). This allows us for the tracking of the gene delivery process.

Activation of TNF-α-AID axis and co-inhibitory signals in coordination with Th1-type immunity in a mouse model recapitulating hepatitis B

Hepatitis B virus (HBV) infection evokes host immune responses that primarily determine the outcome of HBV infection and the clinical features of HBV-associated liver disease. The precise mechanisms by which host factors restrict HBV replication, however, are poorly understood due to the lack of useful animal models that recapitulate immune responses to HBV. Here, we performed comprehensive immunologic gene expression profiling of the liver of a mouse model recapitulating anti-HBV immune response using a high sensitivity direct digital counting system. Anti-HBV cellular immunity with liver inflammation was elicited in mice hydrodynamically injected with a CpG-depleted plasmid encoding hepatitis B surface antigen (HBsAg) gene after preimmunization with HBsAg vaccine. Comprehensive expression analyses revealed the upregulation of Th1-associated genes including tumor necrosis factor (Tnf) and negative regulators of T cell function in the inflamed liver. Interestingly, activation-induced cytidine deaminase (Aicda, termed AID in humans), which reportedly suppresses HBV infection in vitro, was upregulated in hepatocytes in the course of anti-HBV immunity. Hepatocytic expression of Aicda in a Tnf-dependent manner was confirmed by the administration of Tnf antagonist into Aicda-tdTomato mice with anti-HBV immunity. Our findings suggest that activation of Tnf-Aicda axis and co-inhibitory signals to T cells in coordination with Th1-type immunity has critical roles in the immune response against HBV infection.

Inflammation-Induced Expression and Secretion of MicroRNA 122 Leads to Reduced Blood Levels of Kidney-Derived Erythropoietin and Anemia

BACKGROUND & AIMS

Anemia is associated commonly with acute and chronic inflammation, but the mechanisms of their interaction are not clear. We investigated whether microRNA 122 (MIR122), which is generated in the liver and is secreted into the blood, is involved in the development of anemia associated with inflammation.

METHODS

We characterized the primary transcript of the human liver-specific MIR122 using Northern blot, quantitative real-time polymerase chain reaction, and 3' and 5' rapid amplification of cDNA ends analyses. We studied regulation of MIR122 in human hepatocellular carcinoma cell lines (Huh7 and HepG2) as well as in C57BL/6 and mice with disruption of the tumor necrosis factor (Tnf) gene. Liver tissues were collected and analyzed by bioluminescence imaging or immunofluorescence. Inflammation in mice was induced by lipopolysaccharide (LPS) or by cerulein injections. Mice were given 4 successive injections of LPS, leading to inflammation-induced anemia. Steatohepatitis was induced with a choline-deficient, high-fat diet. Hemolytic anemia was stimulated by phenylhydrazine injection. MIR122 was inhibited in mice by tail-vein injection of an oligonucleotide antagonist of MIR122. MicroRNA and messenger RNA levels were determined by quantitative real-time polymerase chain reaction.

RESULTS

The primary transcript of MIR122 spanned 5 kb, comprising 3 exons; the third encodes MIR122. Within the MIR122 promoter region we identified a nuclear factor-κB binding site and showed that RELA (NF-κB p65 subunit), as well as activators of NF-κB (TNF and LPS), increased promoter activity of MIR122. Administration of LPS to mice induced secretion of MIR122 into blood, which required TNF. Secreted MIR122 reached the kidney and reduced expression of erythropoietin (Epo), which we identified as a MIR122 target gene. Injection of mice with an oligonucleotide antagonist of MIR122 increased blood levels of EPO, reticulocytes, and hemoglobin. We found an inverse relationship between blood levels of MIR122 and EPO in mice with acute pancreatitis or steatohepatitis, and also in patients with acute inflammation.

CONCLUSION

In mice, we found that LPS-induced inflammation increases blood levels of MIR122, which reduces expression of Epo in the kidney; this is a mechanism of inflammation-induced anemia. Strategies to block MIR122 in patients with inflammation could reduce the development or progression of anemia.

Reprogramming metabolic pathways in vivo with CRISPR/Cas9 genome editing to treat hereditary tyrosinaemia

Many metabolic liver disorders are refractory to drug therapy and require orthotopic liver transplantation. Here we demonstrate a new strategy, which we call metabolic pathway reprogramming, to treat hereditary tyrosinaemia type I in mice; rather than edit the disease-causing gene, we delete a gene in a disease-associated pathway to render the phenotype benign. Using CRISPR/Cas9 in vivo, we convert hepatocytes from tyrosinaemia type I into the benign tyrosinaemia type III by deleting Hpd (hydroxyphenylpyruvate dioxigenase). Edited hepatocytes (Fah(-/-)/Hpd(-/-)) display a growth advantage over non-edited hepatocytes (Fah(-/-)/Hpd(+/+)) and, in some mice, almost completely replace them within 8 weeks. Hpd excision successfully reroutes tyrosine catabolism, leaving treated mice healthy and asymptomatic. Metabolic pathway reprogramming sidesteps potential difficulties associated with editing a critical disease-causing gene and can be explored as an option for treating other diseases.

Transient Hepatic Overexpression of Insulin-Like Growth Factor 2 Induces Free Cholesterol and Lipid Droplet Formation

Although insulin-like growth factor 2 (IGF2) has been reported to be overexpressed in steatosis and steatohepatitis, a causal role of IGF2 in steatosis development remains elusive. Aim of our study was to decipher the role of IGF2 in steatosis development. Hydrodynamic gene delivery of an Igf2 plasmid used for transient Igf2 overexpression employing codon-optimized plasmid DNA resulted in a strong induction of hepatic Igf2 expression. The exogenously delivered Igf2 had no influence on endogenous Igf2 expression. The downstream kinase AKT was activated in Igf2 animals. Decreased ALT levels mirrored the cytoprotective effect of IGF2. Serum cholesterol was increased and sulfo-phospho-vanillin colorimetric assay confirmed lipid accumulation in Igf2-livers while no signs of inflammation were observed. Interestingly, hepatic cholesterol and phospholipids, determined by thin layer chromatography, and free cholesterol by filipin staining, were specifically increased. Lipid droplet (LD) size was not changed, but their number was significantly elevated. Furthermore, free cholesterol, which can be stored in LDs and has been reported to be critical for steatosis progression, was elevated in Igf2 overexpressing mice. Accordingly, Hmgcr/HmgCoAR was upregulated. To have a closer look at de novo lipid synthesis we investigated expression of the lipogenic transcription factor SREBF1 and its target genes. SREBF1 was induced and also SREBF1 target genes were slightly upregulated. Interestingly, the expression of Cpt1a, which is responsible for mitochondrial fatty acid oxidation, was induced. Hepatic IGF2 expression induces a fatty liver, characterized by increased cholesterol and phospholipids leading to accumulation of LDs. We therefore suggest a causal role for IGF2 in hepatic lipid accumulation.

A Novel Hydrodynamic Injection Mouse Model of HBV Genotype C for the Study of HBV Biology and the Anti-Viral Activity of Lamivudine

BACKGROUND

Absence of an immunocompetent mouse model of persistent hepatitis B virus (HBV) infection has hindered the research of HBV infection and the development of antiviral medications.

OBJECTIVES

In the present study, we aimed to develop a novel HBV genotype C mouse model by hydrodynamic injection (HI) and then used it to evaluate the antiviral activity of lamivudine.

MATERIALS AND METHODS

A quantity of 15 μg of HBV plasmid [pcDNA3.1 (+)-HBV1.3C], adeno-associated virus-HBV1.3C (pAAV-HBV1.3C) or pAAV-HBV1.2A) were injected into male C57BL/6 mice, by HI, accounting for a total of 13 mice per group. Then, lamivudine was administered to mice with sustained HBV viremia, for 4 weeks. Real-time polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry methods were used to detect HBsAg, HBeAg, HBsAb, HBcAg and HBV DNA, in serum or liver of the mice, at indicated time points.

RESULTS

In 60% of the mice injected with pcDNA3.1 (+)-HBV1.3C, HBsAg, HBeAg, HBcAg and HBV DNA persisted for > 20 weeks in liver, post-injection, with no HBsAb appearance. Meanwhile, no significant inflammation was observed in these mice. Compared with pAAV-HBV1.2A and pAAV-HBV1.3C, pcDNA3.1 (+)-HBV1.3C administration led to higher and longer HBV viremia. Furthermore, serum HBV DNA was significantly reduced by lamivudine, after 4 weeks administration, and returned to the original level, after ceasing administration for 1 week, in the mice.

CONCLUSIONS

In conclusion, our observations indicated that pcDNA3.1 (+)-HBV1.3C was superior to AAV/HBV plasmid for establishment of persistent HBV infection by HI, in vivo, and this mouse model could be useful for studies of hepatitis virology and for the development of innovatory treatments for HBV infections.

Sleeping Beauty Transposon Vectors in Liver-directed Gene Delivery of LDLR and VLDLR for Gene Therapy of Familial Hypercholesterolemia

Plasmid-based Sleeping Beauty (SB) transposon vectors were developed and used to deliver genes for low-density lipoprotein and very-low-density lipoprotein receptors (LDLR and VLDLR, respectively) or lacZ reporter into liver of an LDLR-deficient mouse model of familial hypercholesterolemia (FH). SB transposase, SB100x, was used to integrate the therapeutic transposons into mice livers for evaluating the feasibility of the vectors in reducing high blood cholesterol and the progression of atherosclerosis. Hydrodynamic gene delivery of transposon-VLDLR into the livers of the mice resulted in initial 17-19% reductions in plasma cholesterol, and at the later time points, in a significant stabilization of the cholesterol level for the 6.5-month duration of the study compared to the control mice. Transposon-LDLR-treated animals also demonstrated a trend of stabilization in the cholesterol levels in the long term. Vector-treated mice had slightly less lipid accumulation in the liver and reduced aortic atherosclerosis. Clinical chemistry and histological analyses revealed normal liver function and morphology comparable to that of the controls during the follow-up with no safety issues regarding the vector type, transgenes, or the gene transfer method. The study demonstrates the safety and potential benefits of the SB transposon vectors in the treatment of FH.

Massively parallel cis-regulatory analysis in the mammalian central nervous system

Cis-regulatory elements (CREs, e.g., promoters and enhancers) regulate gene expression, and variants within CREs can modulate disease risk. Next-generation sequencing has enabled the rapid generation of genomic data that predict the locations of CREs, but a bottleneck lies in functionally interpreting these data. To address this issue, massively parallel reporter assays (MPRAs) have emerged, in which barcoded reporter libraries are introduced into cells, and the resulting barcoded transcripts are quantified by next-generation sequencing. Thus far, MPRAs have been largely restricted to assaying short CREs in a limited repertoire of cultured cell types. Here, we present two advances that extend the biological relevance and applicability of MPRAs. First, we adapt exome capture technology to instead capture candidate CREs, thereby tiling across the targeted regions and markedly increasing the length of CREs that can be readily assayed. Second, we package the library into adeno-associated virus (AAV), thereby allowing delivery to target organs in vivo. As a proof of concept, we introduce a capture library of about 46,000 constructs, corresponding to roughly 3500 DNase I hypersensitive (DHS) sites, into the mouse retina by ex vivo plasmid electroporation and into the mouse cerebral cortex by in vivo AAV injection. We demonstrate tissue-specific cis-regulatory activity of DHSs and provide examples of high-resolution truncation mutation analysis for multiplex parsing of CREs. Our approach should enable massively parallel functional analysis of a wide range of CREs in any organ or species that can be infected by AAV, such as nonhuman primates and human stem cell–derived organoids.

Novel delivery approaches for cancer therapeutics

Currently, a majority of cancer treatment strategies are based on the removal of tumor mass mainly by surgery. Chemical and physical treatments such as chemo- and radiotherapies have also made a major contribution in inhibiting rapid growth of malignant cells. Furthermore, these approaches are often combined to enhance therapeutic indices. It is widely known that surgery, chemo- and radiotherapy also inhibit normal cells growth. In addition, these treatment modalities are associated with severe side effects and high toxicity which in turn lead to low quality of life. This review encompasses novel strategies for more effective chemotherapeutic delivery aiming to generate better prognosis. Currently, cancer treatment is a highly dynamic field and significant advances are being made in the development of novel cancer treatment strategies. In contrast to conventional cancer therapeutics, novel approaches such as ligand or receptor based targeting, triggered release, intracellular drug targeting, gene delivery, cancer stem cell therapy, magnetic drug targeting and ultrasound-mediated drug delivery, have added new modalities for cancer treatment. These approaches have led to selective detection of malignant cells leading to their eradication with minimal side effects. Lowering multi-drug resistance and involving influx transportation in targeted drug delivery to cancer cells can also contribute significantly in the therapeutic interventions in cancer.

Multifunctional enveloped nanodevices (MENDs)

It is anticipated that nucleic acid medicines will be in widespread use in the future, since they have the potential to cure diseases based on molecular mechanisms at the level of gene expression. However, intelligent delivery systems are required to achieve nucleic acid therapy, since they can perform their function only when they reach the intracellular site of action. We have been developing a multifunctional envelope-type nanodevice abbreviated as MEND, which consists of functional nucleic acids as a core and lipid envelope, and can control not only biodistribution but also the intracellular trafficking of nucleic acids. In this chapter, we review the development and evolution of the MEND by providing several successful examples, including the R8-MEND, the KALA-MEND, the MITO-Porter, the YSK-MEND, and the PALM.

Gene and cell therapy for muscle regeneration

Skeletal muscle injury and healing are multifactorial processes, involving three steps of healing: (1) degeneration and inflammation, (2) regeneration, and (3) fibrosis. Fibrous tissue hinders the muscle's complete recovery and current therapies fail in achieving total muscle recovery. Gene and cell therapy (or both) are potential future treatments for severe muscular injuries. Stem cells' properties associated with growth factors or/and cytokines can improve muscle healing and permit long-term recovery.

Liver lobe and strain difference in gene expression after hydrodynamics-based gene delivery in mice

Hydrodynamics-based gene delivery (HGD) is a widely recognized technique for delivering exogenous DNA with high efficiency to murine hepatocytes. In this study, we investigated stimulation of exogenous DNA uptake and expression using a commercially available reagent for HGD. We also examined which mouse strain and mouse liver lobe would achieve the best gene delivery performance. Mice were injected with a solution containing reporter plasmid DNA or DNA and a gene delivery reagent. One day after the HGD procedure, liver samples were isolated and subjected to biochemical and histochemical analyses. The reporter plasmid DNA showed the strongest signal when the DNA was dissolved in TransIT-EE Hydrodynamic Delivery Solution (Takara Bio Inc., Shiga, Japan). Evaluation of transgene expression in each hepatic lobe in ICR, C57BL/6N, Balb/cA, and B6C3F1 mice showed that ICR mice exhibited the best gene transfer and that the right median lobe had the highest level of transgene expression. These findings suggest the importance of choice in mouse strains and liver lobes when performing gene-based manipulations of the liver.

Transplantation speed offers early hepatocyte engraftment in acute liver injured rats: A translational study with clinical implications

The impact of the rate of intraportal hepatocyte transplantation on early engraftment and repopulation is unclear. The aim of this study was to address this and to improve the engraftment and repopulation efficiencies of hepatocyte transplantation for the treatment of a rat model of acute liver failure in a clinically useful way without preconditioning. Acute hepatic injury was induced into Sprague-Dawley rats with D-galactosamine. Hepatocytes were infused intraportally over a period of 30, 70, or 100 seconds to study early engraftment (2 days) and repopulation (7 days). Three groups had significant differences in hepatocyte engraftment (P = 0.018) and repopulation efficiencies (P = 0.037), and an infusion over a period of 70 seconds produced superior outcomes. After the 70-second infusion, the transplanted cells immediately transmigrated the sinusoidal endothelial layer and rarely accumulated in the portal venules, with liver function improving significantly. The mean first peak pressures, without significant differences, were 14.8 ± 6.5, 17.7 ± 3.7, and 13.6 ± 3.0 mm Hg in the 30-, 70-, and 100-second groups, respectively. Differential hepatocyte transfusion rates contributed to accelerated early engraftment and repopulation in rats with acute liver injury. These proof-of-concept findings are of clinical significance because they are easy to translate into practice.

High persistence rate of hepatitis B virus in a hydrodynamic injection-based transfection model in C3H/HeN mice

AIM: To optimize the viral persistence rate in a hydrodynamic injection (HI) based hepatitis B virus (HBV) transfection mouse model.

METHODS: (1) 5-6-wk-old male C3H/HeN and C57BL/6 mice were hydrodynamically injected with 10 μg endotoxin-free pAAV/HBV1.2 plasmid DNA via the tail vein. Hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) and HBV DNA, both in the serum and liver, were detected at different time points post HI by ELISA, immunohistochemical staining or quantitative polymerase chain reaction (PCR); (2) male C3H/HeN and C57BL/6 mice, either hydrodynamically injected mice at 10 wk post HI or naïve mice, were all immunized subcutaneously with 5 μg HBsAg formulated in complete Freund’s adjuvant three times at a 2-wk interval. Two weeks after the final immunization, splenocytes were isolated for T cell function analysis by ELISPOT assay; and (3) five weeks post HI, C3H/HeN mice were intragastrically administered 0.1 mg/kg entecavir once a day for 14 d, or were intraperitoneally injected with 1 mg/kg interferon (IFN)-α twice a week for 2 wk, or were treated with PBS as controls. The sera were collected and assayed for HBV DNA on days 0, 7 and 14 after drug treatment.

RESULTS: (1) Approximately 90% (22/25) of the injected C3H/HeN mice were still HBsAg-positive at 46 wk post HI, whereas HBsAg in C57BL/6 mice were completely cleared at 24 wk. Serum levels of HBeAg in C3H/HeN mice were higher than those in C57BL/6 mice from 4 wk to 46 wk. HBV DNA levels in the hydrodynamically injected C3H/HeN mice were higher than those in the C57BL/6 mice, both in the serum (from 4 wk to 46 wk) and in the liver (detected at 8 wk and 46 wk post HI). Histology showed that hepatitis B core antigen and HBsAg were expressed longer in the liver of C3H/HeN mice than in C57BL/6; (2) HBsAg specific T cell responses after HBsAg vaccination in hydrodynamically injected C3H/HeN and C57BL/6 mice, or naive control mice were detected by ELISPOT assay. After stimulation with HBsAg, the frequencies of IFN-γ producing splenocytes in the hydrodynamically injected C3H/HeN mice were significantly lower than those in hydrodynamically injected C57BL/6 mice, control C3H/HeN and control C57BL/6 mice, which were 0, 17 ± 7, 18 ± 10, and 41 ± 10 SFCs/10⁶ splenocytes, respectively, and the mean spot sizes showed the same pattern. Even just stimulated with PMA and ionomysin, T-cell responses elicited in the vaccinated control C3H/HeN were much higher than those in hydrodynamically injected C3H/HeN mice; and (3) For drug treatment experiments on the hydrodynamically injected C3H/HeN mice, serum HBV DNA levels in the entecavir treatment group declined (131.2 folds, P < 0.01) on day 7 after treatment and kept going down. In the group of IFN-α treatment, serum HBV DNA levels declined to a lowest point (6.42 folds, P < 0.05) on 7 d after treatment and then rebounded.

CONCLUSION: We have developed a novel HI-based HBV transfection model using C3H/HeN mice, which had a higher HBV persistence rate than the classic C57BL/6 mouse model.

Hydrodynamic delivery

Hydrodynamic delivery (HD) is a broadly used procedure for DNA and RNA delivery in rodents, serving as a powerful tool for gene/protein drug discovery, gene function analysis, target validation, and identification of elements in regulating gene expression in vivo. HD involves a pressurized injection of a large volume of solution into a vasculature. New procedures are being developed to satisfy the need for a safe and efficient gene delivery in clinic. Here, we summarize the fundamentals of HD, its applications, and future perspectives for clinical use.