Gene Editing With CRISPR/Cas9 RNA-Directed Nuclease

Therapeutic Potential of lncRNAs in Regulating Disulfidptosis for Cancer Treatment

Non-coding RNAs (lncRNAs) play critical roles in various cellular processes, including a novel form of regulated cell death known as disulfidptosis, characterized by accumulating protein disulfide bonds and severe endoplasmic reticulum stress. This review highlights the therapeutic potential of lncRNAs in regulating disulfidptosis for cancer treatment, emphasizing their influence on key pathway components such as GPX4, SLC7A11, and PDIA family members. Recent studies have demonstrated that targeting specific lncRNAs can sensitize cancer cells to disulfidptosis, offering a promising approach to cancer therapy. The regulation of disulfidptosis by lncRNAs involves various signaling pathways, including oxidative stress, ER stress, and calcium signaling. This review also discusses the molecular mechanisms underlying lncRNA regulation of disulfidptosis, the challenges of developing lncRNA-based therapies, and the future potential of this rapidly advancing field in cancer research.

Establishment of Mouse Models of Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a chronic vascular disease that commonly affects elderly individuals but has recently increased in younger populations. As the aneurysm grows, it can cause compression symptoms such as abdominal pain, rupture, and bleeding, which are absent in the early stages. Once an AAA ruptures and causes bleeding, the mortality rate is alarmingly high. Currently, the pathogenesis for AAA is unknown, and therapeutic options are limited, necessitating improvement in treatment efficacy. An essential research method for studying the processes and potential treatment of AAA is establishing animal models using mice. The present study provides a detailed overview of the widely used AAA mouse animal models and their construction strategies, advantages, disadvantages, scope of applications, and prospects.

Emerging Medical Technologies and Their Use in Bionic Repair and Human Augmentation

As both the proportion of older people and the length of life increases globally, a rise in age-related degenerative diseases, disability, and prolonged dependency is projected. However, more sophisticated biomedical materials, as well as an improved understanding of human disease, is forecast to revolutionize the diagnosis and treatment of conditions ranging from osteoarthritis to Alzheimer's disease as well as impact disease prevention. Another, albeit quieter, revolution is also taking place within society: human augmentation. In this context, humans seek to improve themselves, metamorphosing through self-discipline or more recently, through use of emerging medical technologies, with the goal of transcending aging and mortality. In this review, and in the pursuit of improved medical care following aging, disease, disability, or injury, we first highlight cutting-edge and emerging materials-based neuroprosthetic technologies designed to restore limb or organ function. We highlight the potential for these technologies to be utilized to augment human performance beyond the range of natural performance. We discuss and explore the growing social movement of human augmentation and the idea that it is possible and desirable to use emerging technologies to push the boundaries of what it means to be a healthy human into the realm of superhuman performance and intelligence. This potential future capability is contrasted with limitations in the right-to-repair legislation, which may create challenges for patients. Now is the time for continued discussion of the ethical strategies for research, implementation, and long-term device sustainability or repair.

Functional identification of two HMGB1 paralogues provides insights into autophagic machinery in teleost

High mobility group box 1 (HMGB1) is a multifunctional regulator that plays different roles in various physiological and pathological processes including cell development, autophagy, inflammation, tumor metastasis, and cell death based on its cellular localization. Unlike mammalian HMGB1, two HMGB1 paralogues (HMGB1a and HMGB1b) have been found in fathead minnow and other fish species and its function as an inflammatory cytokine has been well investigated. However, the role of fish HMGB1 in autophagy regulation has not been well clarified. In the present study, we generated HMGB1 paralogues single (HMGB1a-/- and HMGB1b-/-) and double knockout (DKO) epithelioma papulosum cyprini (EPC) cells from fathead minnow by CRISPR/Cas9 system, and the knockout efficiency of these genes was verified at both gene and protein levels. In this context, the effects of HMGB1 gene knockout on the protein expression of microtubule-associated protein 1 light chain 3 II (LC3-II), an autophagy marker, were determined, showing that single knockout of two HMGB1 paralogues significantly decreased the expression of LC3-II, and these inhibitory effects were further amplified in HMGB1 DKO cells under both basal and rapamycin treatment conditions, indicating the role of two HMGB1 paralogues in fish autophagy. In agreement with this notion, overexpression of HMGB1a or HMGB1b with Flag-tag markedly upregulated LC3-II protein expression. Interestingly, overexpressing two paralogues distributed in both cytoplasm and nucleus. Finally, the role of HMGB1-mediated autophagy was further explored, finding that HMGB1 could interact with Beclin1, a key initiation factor of autophagy. Taken together, these findings highlighted the role of HMGB1 paralogues as the autophagy regulator and increased our understanding of autophagic machinery in teleost.

Knockdown of NEAT1 prevents post-stroke lipid droplet agglomeration in microglia by regulating autophagy

BACKGROUND

Lipid droplets (LD), lipid-storing organelles containing neutral lipids like glycerolipids and cholesterol, are increasingly accepted as hallmarks of inflammation. The nuclear paraspeckle assembly transcript 1 (NEAT1), a long non-coding RNA with over 200 nucleotides, exerts an indispensable impact on regulating both LD agglomeration and autophagy in multiple neurological disorders. However, knowledge as to how NEAT1 modulates the formation of LD and associated signaling pathways is limited.

METHODS

In this study, primary microglia were isolated from newborn mice and exposed to oxygen-glucose-deprivation/reoxygenation (OGD/R). To further explore NEAT1-dependent mechanisms, an antisense oligonucleotide (ASO) was adopted to silence NEAT1 under in vitro conditions. Studying NEAT1-dependent interactions with regard to autophagy and LD agglomeration under hypoxic conditions, the inhibitor and activator of autophagy 3-methyladenine (3-MA) and rapamycin (RAPA) were used, respectively. In a preclinical stroke model, mice received intraventricular injections of ASO NEAT1 or control vectors in order to yield NEAT1 knockdown. Analysis of readout parameters included qRT-PCR, immunofluorescence, western blot assays, and behavioral tests.

RESULTS

Microglia exposed to OGD/R displayed a temporal pattern of NEAT1 expression, peaking at four hours of hypoxia followed by six hours of reoxygenation. After effectively silencing NEAT1, LD formation and autophagy-related proteins were significantly repressed in hypoxic microglia. Stimulating autophagy in ASO NEAT1 microglia under OGD/R conditions by means of RAPA reversed the downregulation of LD agglomeration and perilipin 2 (PLIN2) expression. On the contrary, application of 3-MA promoted repression of both LD agglomeration and expression of the LD-associated protein PLIN2. Under in vivo conditions, NEAT1 was significantly increased in mice at 24 h post-stroke. Knockdown of NEAT1 significantly alleviated LD agglomeration and inhibited autophagy, resulting in improved cerebral perfusion, reduced brain injury and increased neurological recovery.

CONCLUSION

NEAT1 is a key player of LD agglomeration and autophagy stimulation, and NEAT1 knockdown provides a promising therapeutic value against stroke.

A Self-Assembling Peptide as a Model for Detection of Colorectal Cancer

Patient-derived organoid (PDO) models have been widely used in precision medicine. The inability to standardize organoid creation in pre-clinical models has become apparent. The common mouse-derived extracellular matrix can no longer meet the requirements for the establishment of PDO models. Therefore, in order to develop effective methods for 3D cultures of organoids, we designed a self-assembling peptide, namely DRF3, which can be self-assembled into ordered fibrous scaffold structures. Here, we used the co-assembly of self-assembling peptide (SAP) and collagen type I, fibronectin, and laminin (SAP-Matrix) to co-simulate the extracellular matrix, which significantly reduced the culture time of PDO, improved the culture efficiency, and increased the self-assembly ability of cells. Compared with the results from the 2D cell line, the PDO showed a more significant expression of cancer-related genes. During organoid self-assembly, the expression of cancer-related genes is increased. These findings provide a theoretical basis for the establishment of precision molecular modeling platforms in the future.

Long-Term Biodistribution and Safety of Human Dystrophin Expressing Chimeric Cell Therapy After Systemic-Intraosseous Administration to Duchenne Muscular Dystrophy Model

Duchenne muscular dystrophy (DMD) is a lethal disease caused by X-linked mutations in the dystrophin gene. Dystrophin deficiency results in progressive degeneration of cardiac, respiratory and skeletal muscles leading to premature death due to cardiopulmonary complications. Currently, no cure exists for DMD. Based on our previous reports confirming a protective effect of human dystrophin expressing chimeric (DEC) cell therapy on cardiac, respiratory, and skeletal muscle function after intraosseous administration, now we assessed long-term safety and biodistribution of human DEC therapy for potential clinical applications in DMD patients. Safety of different DEC doses (1 × 10⁶ and 5 × 10⁶) was assessed at 180 days after systemic-intraosseous administration to mdx/scid mice, a model of DMD. Assessments included: single cell gel electrophoresis assay (COMET assay) to confirm lack of genetic toxicology, magnetic resonance imaging (MRI) for tumorigenicity, and body, muscle and organ weights. Human DEC biodistribution to the target (heart, diaphragm, gastrocnemius muscle) and non-target (blood, bone marrow, lung, liver, spleen) organs was detected by flow cytometry assessment of HLA-ABC markers. Human origin of dystrophin was verified by co-localization of dystrophin and human spectrin by immunofluorescence. No complications were observed after intraosseous transplant of human DEC. COMET assay of donors and fused DEC cells confirmed lack of DNA damage. Biodistribution analysis of HLA-ABC expression revealed dose-dependent presence of human DEC cells in target organs, whereas negligible presence was detected in non-target organs. Human origin of dystrophin in the heart, diaphragm and gastrocnemius muscle was confirmed by co-localization of dystrophin expression with human spectrin. MRI revealed no evidence of tumor formation. Body mass and muscle and organ weights were stable and comparable to vehicle controls, further confirming DEC safety at 180 days post- transplant. This preclinical study confirmed long-term local and systemic safety of human DEC therapy at 180 days after intraosseous administration. Thus, DEC can be considered as a novel myoblast based advanced therapy medicinal product for DMD patients.

Long-Term Protective Effect of Human Dystrophin Expressing Chimeric (DEC) Cell Therapy on Amelioration of Function of Cardiac, Respiratory and Skeletal Muscles in Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy (DMD) is a lethal disease caused by mutations in dystrophin encoding gene, causing progressive degeneration of cardiac, respiratory, and skeletal muscles leading to premature death due to cardiac and respiratory failure. Currently, there is no cure for DMD. Therefore, novel therapeutic approaches are needed for DMD patients.

We have previously reported functional improvements which correlated with increased dystrophin expression following administration of dystrophin expressing chimeric (DEC) cells of myoblast origin to the mdx mouse models of DMD.

In the current study, we confirmed dose-dependent protective effect of human DEC therapy created from myoblasts of normal and DMD-affected donors, on restoration of dystrophin expression and amelioration of cardiac, respiratory, and skeletal muscle function at 180 days after systemic-intraosseous DEC administration to mdx/scid mouse model of DMD. Functional improvements included maintenance of ejection fraction and fractional shortening levels on echocardiography, reduced enhanced pause and expiration time on plethysmography and improved grip strength and maximum stretch induced contraction of skeletal muscles. Improved function was associated with amelioration of mdx muscle pathology revealed by reduced muscle fibrosis, reduced inflammation and improved muscle morphology confirmed by reduced number of centrally nucleated fibers and normalization of muscle fiber diameters. Our findings confirm the long-term systemic effect of DEC therapy in the most severely affected by DMD organs including heart, diaphragm, and long skeletal muscles.

These encouraging preclinical data introduces human DEC as a novel therapeutic modality of Advanced Therapy Medicinal Product (ATMP) with the potential to improve or halt the progression of DMD and enhance quality of life of DMD patients.

Dual-sgRNA CRISPR/Cas9 knockout of PD-L1 in human U87 glioblastoma tumor cells inhibits proliferation, invasion, and tumor-associated macrophage polarization

Programmed death ligand 1 (PD-L1) plays a key role in glioblastoma multiforme (GBM) immunosuppression, vitality, proliferation, and migration, and is therefore a promising target for treating GBM. CRISPR/Cas9-mediated genomic editing can delete both cell surface and intracellular PD-L1. This systemic deliverable genomic PD-L1 deletion system can be used as an effective anti-GBM therapy by inhibiting tumor growth and migration, and overcoming immunosuppression. To target PD-L1 for CRISPR/Cas9 gene editing, we first identified two single guide RNA (sgRNA) sequences located on PD-L1 exon 3. The first sgRNA recognizes the forward strand of human PD-L1 near the beginning of exon 3 that allows editing by Cas9 at approximately base pair 82 (g82). The second sgRNA recognizes the forward strand of exon 3 that directs cutting at base pair 165 (g165). A homology-directed repair template (HDR) combined with the dual-sgRNAs was used to improve PD-L1 knockout specificity and efficiency. sgRNAs g82 and g165 were cloned into the multiplex CRISPR/Cas9 assembly system and co-transfected with the HDR template in human U87 GBM cells (g82/165 + HDR). T7E1 analysis suggests that the dual-sgRNA CRISPR/Cas9 strategy with a repair template was capable of editing the genomic level of PD-L1. This was further confirmed by examining PD-L1 protein levels by western blot and immunofluorescence assays. Western blot analysis showed that the dual-sgRNAs with the repair template caused a 64% reduction of PD-L1 protein levels in U87 cells, while immunostaining showed a significant reduction of intracellular PD-L1. PD-L1 deletion inhibited proliferation, growth, invasion and migration of U87 cells, indicating intracellular PD-L1 is necessary for tumor progression. Importantly, U87 cells treated with g82/165 + HDR polarized tumor-associated macrophages (TAM) toward an M1 phenotype, as indicated by an increase in TNF-α and a decrease in IL-4 secretions. This was further confirmed with flow cytometry that showed an increase in the M1 markers Ly6C + and CD80 +, and a decrease in the M2 marker CD206 + both in vitro and in vivo. Utilizing dual-sgRNAs and an HDR template with the CRISPR/Cas9 gene-editing system is a promising avenue for the treatment of GBM.

Updated perspectives on vascular cell specification and pluripotent stem cell-derived vascular organoids for studying vasculopathies

Vasculopathy is a pathological process occurring in the blood vessel wall, which could affect the haemostasis and physiological functions of all the vital tissues/organs and is one of the main underlying causes for a variety of human diseases including cardiovascular diseases. Current pharmacological interventions aiming to either delay or stop progression of vasculopathies are suboptimal, thus searching novel, targeted, risk-reducing therapeutic agents, or vascular grafts with full regenerative potential for patients with vascular abnormalities are urgently needed. Since first reported, pluripotent stem cells (PSCs), particularly human-induced PSCs, have open new avenue in all research disciplines including cardiovascular regenerative medicine and disease remodelling. Assisting with recent technological breakthroughs in tissue engineering, in vitro construction of tissue organoid made a tremendous stride in the past decade. In this review, we provide an update of the main signal pathways involved in vascular cell differentiation from human PSCs and an extensive overview of PSC-derived tissue organoids, highlighting the most recent discoveries in the field of blood vessel organoids as well as vascularization of other complex tissue organoids, with the aim of discussing the key cellular and molecular players in generating vascular organoids.

The Advance of CRISPR-Cas9-Based and NIR/CRISPR-Cas9-Based Imaging System

The study of different genes, chromosomes and the spatiotemporal relationship between them is of great significance in the field of biomedicine. CRISPR-Cas9 has become the most widely used gene editing tool due to its excellent targeting ability. In recent years, a series of advanced imaging technologies based on Cas9 have been reported, providing fast and convenient tools for studying the sites location of genome, RNA, and chromatin. At the same time, a variety of CRISPR-Cas9-based imaging systems have been developed, which are widely used in real-time multi-site imaging in vivo. In this review, we summarized the component and mechanism of CRISPR-Cas9 system, overviewed the NIR imaging and the application of NIR fluorophores in the delivery of CRISPR-Cas9, and highlighted advances of the CRISPR-Cas9-based imaging system. In addition, we also discussed the challenges and potential solutions of CRISPR-Cas9-based imaging methods, and looked forward to the development trend of the field.

Identification of a Novel Cleavage Site and Confirmation of the Effectiveness of NgAgo Gene Editing on RNA Targets

Clusters of regularly interspaced short palindromic repeats (CRISPR)/Cas systems have a powerful ability to edit DNA and RNA targets. However, the need for a specific recognition site, protospacer adjacent motif (PAM), of the CRISPR/Cas system limits its application in gene editing. Some Argonaute (Ago) proteins have endonuclease functions under the guidance of 5' phosphorylated or hydroxylated guide DNA (gDNA). The NgAgo protein might perform RNA gene editing at 37 °C, suggesting its application in mammalian cells; however, its mechanisms are unclear. In the present study, the target of NgAgo in RNA was confirmed in vitro and in vivo. Then, an in vitro RNA cleavage system was designed and the cleavage site was verified by sequencing. Furthermore, NgAgo and gDNA were transfected into cells to cleave an intracellular target sequence. We demonstrated targeted degradation of GFP, HCV, and AKR1B10 RNAs in a gDNA-dependent manner by NgAgo both in vitro and in vivo, but no effect on DNA was observed. Sequencing demonstrated that the cleavage sites are located at the 3' of the target RNA which is recognized by 5' sequence of the gDNA. These results confirmed that NgAgo-gDNA cleaves RNA not DNA. We observed that the cleavage site is located at the 3' of the target RNA, which is a new finding that has not been reported in the past.

CRISPR/Cas9/AAV9-mediated in vivo editing identifies MYC regulation of 3D genome in skeletal muscle stem cell

Skeletal muscle satellite cells (SCs) are stem cells responsible for muscle development and regeneration. Although CRISPR/Cas9 has been widely used, its application in endogenous SCs remains elusive. Here, we generate mice expressing Cas9 in SCs and achieve robust editing in juvenile SCs at the postnatal stage through AAV9-mediated short guide RNA (sgRNA) delivery. Additionally, we reveal that quiescent SCs are resistant to CRISPR/Cas9-mediated editing. As a proof of concept, we demonstrate efficient editing of master transcription factor (TF) Myod1 locus using the CRISPR/Cas9/AAV9-sgRNA system in juvenile SCs. Application on two key TFs, MYC and BCL6, unveils distinct functions in SC activation and muscle regeneration. Particularly, we reveal that MYC orchestrates SC activation through regulating 3D genome architecture. Its depletion results in strengthening of the topologically associating domain boundaries thus may affect gene expression. Altogether, our study establishes a platform for editing endogenous SCs that can be harnessed to elucidate the functionality of key regulators governing SC activities.

Human dystrophin expressing chimeric (DEC) cell therapy ameliorates cardiac, respiratory, and skeletal muscle's function in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a progressive and lethal disease, caused by X‐linked mutations of the dystrophin encoding gene. The lack of dystrophin leads to muscle weakness, degeneration, fibrosis, and progressive loss of skeletal, cardiac, and respiratory muscle function resulting in premature death due to the cardiac and respiratory failure. There is no cure for DMD and current therapies neither cure nor arrest disease progression. Thus, there is an urgent need to develop new approaches and safer therapies for DMD patients. We have previously reported functional improvements which correlated with increased dystrophin expression following transplantation of dystrophin expressing chimeric (DEC) cells of myoblast origin to the mdx mouse models of DMD. In this study, we demonstrated that systemic‐intraosseous transplantation of DEC human cells derived from myoblasts of normal and DMD‐affected donors, increased dystrophin expression in cardiac, respiratory, and skeletal muscles of the mdx/scid mouse model of DMD. DEC transplant correlated with preservation of ejection fraction and fractional shortening on echocardiography, improved respiratory function on plethysmography, and improved strength and function of the limb skeletal muscles. Enhanced function was associated with improved muscle histopathology, revealing reduced mdx pathology, fibrosis, decreased inflammation, and preserved muscle morphology and architecture. Our findings confirm that DECs generate a systemic protective effect in DMD‐affected target organs. Therefore, DECs represents a novel therapeutic approach with the potential to preserve or enhance multiorgan function of the skeletal, cardiac, and respiratory muscles critical for the well‐being of DMD patients.

Transcriptome-Wide Analysis to Identify the Inflammatory Role of lncRNA Neat1 in Experimental Ischemic Stroke

Background

Ischemic stroke is one of the leading causes of mortality and disability worldwide. Following stroke, there is secondary neuroinflammation that promotes further injury. Identifying the long non-coding RNA (lncRNA) involved in neuroinflammation after cerebral ischemic stroke will promote the discovery of potential therapeutic targets.

Methods

We identified differentially expressed genes from genome-wide RNA-seq profiles of mice with focal ischemia using Gene Ontology Term Enrichment, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment analyses. Immune cell infiltration deconvolution, protein-protein interaction network construction, and co-expression network analyses were also used to screen lncRNAs. In further experiments, lncRNA Neat1 knockdown animal models were developed by intraventricular injection of the antisense oligonucleotide before performing middle cerebral artery occlusion (MCAO). An enzyme-linked immunosorbent assay was performed to measure the level of cytokines. Hematoxylin-eosin staining and immunohistochemical staining were used to observe the changes in morphology.

Results

Enrichment analysis revealed that differential mRNAs induced neuroinflammation after MCAO. Immune deconvolution showed that the proportion of microglia gradually increased while monocytes decreased within 24 h. We identified six hub lncRNAs (Neat1, Gm10827, Trp53cor1, Mir670hg, C730002L08Rik, and Mir181a-hg) that were highly correlated with activated-microglia mRNAs (cor > 0.8). We found that Neat1 had the highest correlation coefficient with pro-inflammatory factor mRNA levels. In vivo experiments demonstrated that Neat1 had abnormally high expression after MCAO. Knockdown of Neat1 could significantly alleviate brain damage by reducing the number of activated microglia and reducing their release of proinflammatory cytokines.

Conclusion

We identified inflammation-associated lncRNA Neat1 as crucial, which means it is a potential target for ischemic stroke treatment.

Guiding-Strand-Controlled DNA Nucleases with Enhanced Specificity and Tunable Kinetics for DNA Mutation Detection

Nucleases are powerful tools in various biomedical applications, such as genetic engineering, biosensing, and molecular diagnosis. However, the commonly used nucleases (endonuclease IV, apurinic/apyrimidinic endonuclease-1, and λ exonuclease) are prone to the nonspecific cleavage of single-stranded DNA, making the desired reactions extremely low-yield and unpredictable. Herein, we have developed guiding-strand-controlled nuclease systems and constructed theoretical kinetic models to explain their mechanisms of action. The models displayed excellent agreement with the experimental results, making the kinetics highly predictable and tunable. Our method inhibited the nonspecific cleavage of single-stranded probes while maintaining highly efficient cleavage of double-stranded DNA. We also demonstrated the clinical practicability of the method by detecting a low-frequency mutation in a genomic DNA sample extracted from the blood of a patient with cancer. The limit of detection could be 0.01% for PTEN rs121909219. We believe that our findings provide a powerful tool for the field and the established model provides us a deeper understanding of the enzymatic activities of DNA nucleases.

Glioma stem cells invasive phenotype at optimal stiffness is driven by MGAT5 dependent mechanosensing

BACKGROUND

Glioblastomas stem-like cells (GSCs) by invading the brain parenchyma, remains after resection and radiotherapy and the tumoral microenvironment become stiffer. GSC invasion is reported as stiffness sensitive and associated with altered N-glycosylation pattern. Glycocalyx thickness modulates integrins mechanosensing, but details remain elusive and glycosylation enzymes involved are unknown. Here, we studied the association between matrix stiffness modulation, GSC migration and MGAT5 induced N-glycosylation in fibrillar 3D context.

METHOD

To mimic the extracellular matrix fibrillar microenvironments, we designed 3D-ex-polyacrylonitrile nanofibers scaffolds (NFS) with adjustable stiffnesses by loading multiwall carbon nanotubes (MWCNT). GSCs neurosphere were plated on NFSs, allowing GSCs migration and MGAT5 was deleted using CRISPR-Cas9.

RESULTS

We found that migration of GSCs was maximum at 166 kPa. Migration rate was correlated with cell shape, expression and maturation of focal adhesion (FA), Epithelial to Mesenchymal Transition (EMT) proteins and (β1,6) branched N-glycan binding, galectin-3. Mutation of MGAT5 in GSC inhibited N-glycans (β1-6) branching, suppressed the stiffness dependence of migration on 166 kPa NFS as well as the associated FA and EMT protein expression.

CONCLUSION

MGAT5 catalysing multibranched N-glycans is a critical regulators of stiffness induced invasion and GSCs mechanotransduction, underpinning MGAT5 as a serious target to treat cancer.

A short overview of CRISPR-Cas technology and its application in viral disease control

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) together with CRISPR-associated (Cas) proteins have catalysed a revolution in genetic engineering. Native CRISPR-Cas systems exist in many bacteria and archaea where they provide an adaptive immune response through sequence-specific degradation of an invading pathogen's genome. This system has been reconfigured for use in genome editing, drug development, gene expression regulation, diagnostics, the prevention and treatment of cancers, and the treatment of genetic and infectious diseases. In recent years, CRISPR-Cas systems have been used in the diagnosis and control of viral diseases, for example, CRISPR-Cas12/13 coupled with new amplification techniques to improve the specificity of sequence-specific fluorescent probe detection. Importantly, CRISPR applications are both sensitive and specific and usually only require commonly available lab equipment. Unlike the canonical Cas9 which is guided to double-stranded DNA sites of interest, Cas13 systems target RNA sequences and thus can be employed in strategies directed against RNA viruses or for transcriptional silencing. Many challenges remain for these approach, including issues with specificity and the requirement for better mammalian delivery systems. In this review, we summarize the applications of CRISPR-Cas systems in controlling mammalian viral infections. Following necessary improvements, it is expected that CRISPR-Cas systems will be used effectively for such applications in the future.

Generation of VEGF knock-in Cashmere goat via the CRISPR/Cas9 system

Cashmere is a rare and specialised animal fibre, which grows on the outer skin of goats. Owing its low yield and soft, light, and warm properties, it has a high economic value. Here, we attempted to improve existing cashmere goat breeds by simultaneously increasing their fibre length and cashmere yield. We attempted this by knocking in the vascular endothelial growth factor (VEGF) at the fibroblast growth factor 5(FGF5) site using a gene editing technology and then studying its hair growth-promoting mechanisms. We show that a combination of RS-1 and NU7441 significantly improve the efficiency of CRISPR/Cas9-mediated, homologous-directed repair without affecting the embryo cleavage rate or the percentages of embryos at different stages. In addition, we obtained a cashmere goat, which integrated the VEGF gene at the FGF5 site, and the cashmere yield and fibre length of this gene-edited goat were improved. Through next-generation sequencing, we found that the up-regulation of VEGF and the down-regulation of FGF5 affected the cell cycle, proliferation, and vascular tone through the PI3K-AKT signalling pathway and at extracellular matrix-receptor interactions. Owing to this, the gene-edited cashmere goat showed impressive cashmere performance. Overall, in this study, we generated a gene-edited cashmere goat by integrating VEGF at the FGF5 site and provided an animal model for follow-up research on hair growth mechanisms.

LncRNA regulation: New frontiers in epigenetic solutions to drug chemoresistance

Long-noncoding RNAs (lncRNAs) have been shown to participate in sensitizing or de-sensitizing cancer cells to chemical drugs during cancer therapeutics. Notably, a plethora of lncRNAs have been confirmed to be associated with epigenetic controllers and regulate histone protein modification or DNA methylation states in the process of gene transcription. This correlation between lncRNAs and epigenetic regulators can induce the expression of core genes to trigger drug resistance. In addition, epigenetic signatures are considered to be effective and attractive biomarkers for monitoring drug therapeutic effects because they are inheritable, dynamic, and reversible. Therefore, the regulatory mechanism between lncRNAs and epigenetic machinery can serve as a novel indicator and target to overcome or reverse drug resistance in cancer therapy. In this review, we also presented a curated selection of computational tools (including online databases and network analysis) in the area of epigenetics. A classic workflow for lncRNA expression network analysis is presented, providing guidance for non-bioinformaticians to identify significant correlation between lncRNAs and other biomolecules.

Cardiac Protection after Systemic Transplant of Dystrophin Expressing Chimeric (DEC) Cells to the mdx Mouse Model of Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy (DMD) is a progressive lethal disease caused by X-linked mutations of the dystrophin gene. Dystrophin deficiency clinically manifests as skeletal and cardiac muscle weakness, leading to muscle wasting and premature death due to cardiac and respiratory failure. Currently, no cure exists. Since heart disease is becoming a leading cause of death in DMD patients, there is an urgent need to develop new more effective therapeutic strategies for protection and improvement of cardiac function. We previously reported functional improvements correlating with dystrophin restoration following transplantation of Dystrophin Expressing Chimeric Cells (DEC) of myoblast origin in the mdx and mdx/scid mouse models. Here, we confirm positive effect of DEC of myoblast (MB^wt/MB^mdx) and mesenchymal stem cells (MB^wt/MSC^mdx) origin on protection of cardiac function after systemic DEC transplant. Therapeutic effect of DEC transplant (0.5 × 10⁶) was assessed by echocardiography at 30 and 90 days after systemic-intraosseous injection to the mdx mice. At 90 days post-transplant, dystrophin expression in cardiac muscles of DEC injected mice significantly increased (15.73% ± 5.70 –MB^wt/MB^mdx and 5.22% ± 1.10 – MB^wt/MSC^mdx DEC) when compared to vehicle injected controls (2.01% ± 1.36) and, correlated with improved ejection fraction and fractional shortening on echocardiography. DEC lines of MB and MSC origin introduce a new promising approach based on the combined effects of normal myoblasts with dystrophin delivery capacities and MSC with immunomodulatory properties. Our study confirms feasibility and efficacy of DEC therapy on cardiac function and represents a novel therapeutic strategy for cardiac protection and muscle regeneration in DMD.

Great expectations: virus-mediated gene therapy in neurological disorders

Gene therapy (GT) has tremendous potential for the treatment of neurological disorders to transform patient care. The successful application of virus-mediated GT to treat spinal muscular atrophy is a significant milestone, serving to accelerate similar progress in a spectrum of neurological conditions, with more than 50 clinical trials currently underway, across neurodevelopmental, neurodegenerative, muscular dystrophy, epilepsy, chronic pain and neoplastic diseases. This review provides an overview of the key features of virus-mediated GT, paradigms of delivery and dosing, potential risks and highlights ongoing research to optimise safe and effective delivery of vectors into the nervous system. Examples of the application of GT in various neurological diseases alongside clinical development challenges will be presented. As the development and translation of GTs gain pace, success can only ultimately be realised for patients following implementation in the health system. The challenges and controversies of daunting costs, ethics, early diagnosis and health system readiness will require innovative pricing schemes, regulatory policies, education and organisation of a skilled workforce to deliver of high-quality care in clinical practice as we prepare for advanced therapeutics in neurology.

Science Runs and the Debate Brakes: Somatic Gene-Editing as a New Tool for Gender-Specific Medicine in Alzheimer's Disease

Gender-specific medicine is a discipline that studies the influence of sex and gender on physiology, pathophysiology, and diseases. One example in light of how a genetic-based disease among other diseases, that impact on sex, can be represented by the risk of developing dementia or Alzheimer's disease. The question that comes into focus is whether gene-editing can represent a new line of investigation to be explored in the development of personalized, gender-specific medicine that guarantees gender equity in health policies. This article aims to discuss the relevance of adopting a gender-specific focus on gene-editing research, considered as a way of contributing to the advance of medicine's understanding, treatment, and prevention of dementia, particularly Alzheimer's disease. The development or improvement of cures could take advantage of the knowledge of the gender diversity in order to ascertain and develop differential interventions also at the genetic level between women and men, and this deserves special attention and deep ethical reflection.

Recent developments in regenerative ophthalmology

Regenerative medicine (RM) is one of the most promising disciplines for advancements in modern medicine, and regenerative ophthalmology (RO) is one of the most active fields of regenerative medicine. This review aims to provide an overview of regenerative ophthalmology, including the range of tools and materials being used, and to describe its application in ophthalmologic subspecialties, with the exception of surgical implantation of artificial tissues or organs (e.g., contact lens, artificial cornea, intraocular lens, artificial retina, and bionic eyes) due to space limitations. In addition, current challenges and limitations of regenerative ophthalmology are discussed and future directions are highlighted.

Development and Application of CRISPR/Cas in Microbial Biotechnology

The clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas) system has been rapidly developed as versatile genomic engineering tools with high efficiency, accuracy and flexibility, and has revolutionized traditional methods for applications in microbial biotechnology. Here, key points of building reliable CRISPR/Cas system for genome engineering are discussed, including the Cas protein, the guide RNA and the donor DNA. Following an overview of various CRISPR/Cas tools for genome engineering, including gene activation, gene interference, orthogonal CRISPR systems and precise single base editing, we highlighted the application of CRISPR/Cas toolbox for multiplexed engineering and high throughput screening. We then summarize recent applications of CRISPR/Cas systems in metabolic engineering toward production of chemicals and natural compounds, and end with perspectives of future advancements.

Navigating Uncertainties: How to Assess Welfare and Harm in Genetically Altered Animals Responsibly-A Practical Guideline

Simple Summary

When using animals in research, ethical aspects must be included in the project evaluation process. As one important part, a harm–benefit analysis (HBA) should be carried out in order to approve projects in line with the EU Directive 2010/63/EU, which sets out the rules for animal experiments in Europe. These regulations state that the harms and benefits of a project should be assessed and weighed before the project starts. Assessment of harms caused by scientific procedure is a precondition for ethical evaluation. In this context, projects that involve genetically altered (GA) lines raise new issues. A significant lack of knowledge surrounds new GA lines, making it difficult and sometimes impossible to estimate harm prospectively with sufficient certainty since it is not predictable what sort of harm—if at all—the animals are going to experience. Therefore, this contribution aims to deal with the challenges of harm assessment in GA animals and their implications for welfare assessment and the HBA. A practical guideline is presented herein to serve as guidance for relevant harm factors and address the main challenges, particularly when dealing with uncertainties in project evaluation.

Abstract

The use of animals in research requires careful ethical consideration of whether the burden on the animals is justified. As one important part of the project evaluation, a harm–benefit analysis (HBA) must be carried out in order to approve projects in line with the EU Directive 2010/63/EU. This implies that harms and benefits must be assessed prospectively beforehand in order to weigh them. Although there are different methods of weighing, it is clear that an assessment of prospective harms and benefits is a precondition for any weighing procedure. In this context, projects that use genetically altered (GA) lines raise new issues. A unique challenge when using GA lines is the significant lack of knowledge in this context, making it difficult and sometimes impossible to estimate harm prospectively with sufficient certainty, since it is not predictable what sort of harm—if at all—the animals are going to experience. Therefore, this contribution aims to deal with the challenges of harm assessment in GA animals and their implications for welfare assessment and the HBA. A practical guideline is presented herein to serve as guidance for relevant harm factors and address the main challenges, particularly when dealing with uncertainties in the process of HBA.

Gene Therapy for the Heart Lessons Learned and Future Perspectives

While clinical gene therapy celebrates its first successes, with several products already approved for clinical use and several hundreds in the final stages of the clinical approval pipeline, there is not a single gene therapy approach that has worked for the heart. Here, we review the past experience gained in the several cardiac gene therapy clinical trials that had the goal of inducing therapeutic angiogenesis in the ischemic heart and in the attempts at modulating cardiac function in heart failure. Critical assessment of the results so far achieved indicates that the efficiency of cardiac gene delivery remains a major hurdle preventing success but also that improvements need to be sought in establishing more reliable large animal models, choosing more effective therapeutic genes, better designing clinical trials, and more deeply understanding cardiac biology. We also emphasize a few areas of cardiac gene therapy development that hold great promise for the future. In particular, the transition from gene addition studies using protein-coding cDNAs to the modulation of gene expression using small RNA therapeutics and the improvement of precise gene editing now pave the way to applications such as cardiac regeneration after myocardial infarction and gene correction for inherited cardiomyopathies that were unapproachable until a decade ago.

Gene Therapy for Angelman Syndrome: Contemporary Approaches and Future Endeavors

Background:

Angelman Syndrome (AS) is a congenital non inherited neurodevelopmental disorder. The contemporary AS management is symptomatic and it has been accepted that gene therapy may play a key role in the treatment of AS.

Objective:

The purpose of this study is to summarize existing and suggested gene therapy approaches to Angelman syndrome.

Methods:

This is a literature review. Pubmed and Scopus databases were researched with keywords (gene therapy, Angelman’s syndrome, neurological disorders, neonates). Peer-reviewed studies that were closely related to gene therapies in Angelman syndrome and available in English, Greek, Ukrainian or Indonesian were included. Studies that were published before 2000 were excluded and did not align with the aforementioned criteria.

Results:

UBE3A serves multiple roles in signaling and degradation procedures. Although the restoration of UBE3A expression rather than targeting known activities of the molecule would be the optimal therapeutic goal, it is not possible so far. Reinstatement of paternal UBE3A appears as an adequate alternative. This can be achieved by administering topoisomerase-I inhibitors or reducing UBE3A antisense transcript (UBE3A-ATS), a molecule which silences paternal UBE3A.

Conclusion:

Understanding UBE3A imprinting unravels the path to an etiologic treatment of AS. Gene therapy models tested on mice appeared less effective than anticipated pointing out that activation of paternal UBE3A cannot counteract the existing CNS defects. On the other hand, targeting abnormal downstream cell signaling pathways has provided promising rescue effects. Perhaps, combined reinstatement of paternal UBE3A expression with abnormal signaling pathways-oriented treatment is expected to provide better therapeutic effects. However, AS gene therapy remains debatable in pharmacoeconomics and ethics context.

Challenges associated with homologous directed repair using CRISPR-Cas9 and TALEN to edit the DMD genetic mutation in canine Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene that abolish the expression of dystrophin protein. Dogs with the genetic homologue, golden retriever muscular dystrophy dog (GRMD), have a splice site mutation that leads to skipping of exon 7 and a stop codon in the DMD transcript. Gene editing via homology-directed repair (HDR) has been used in the mdx mouse model of DMD but not in GRMD. In this study, we used clustered regularly interspaced short palindromic repeats (CRISPR) and transcription activator-like effector nucleases (TALEN) to restore dystrophin expression via HDR in myoblasts/myotubes and later via intramuscular injection of GRMD dogs. In vitro, DNA and RNA were successfully corrected but dystrophin protein was not translated. With intramuscular injection of two different guide arms, sgRNA A and B, there was mRNA expression and Sanger sequencing confirmed inclusion of exon 7 for all treatments. On Western blot analysis, protein expression of up to 6% of normal levels was seen in two dogs injected with sgRNA B and up to 16% of normal in one dog treated with sgRNA A. TALEN did not restore any dystrophin expression. While there were no adverse effects, clear benefits were not seen on histopathologic analysis, immunofluorescence microscopy, and force measurements. Based on these results, methods must be modified to increase the efficiency of HDR-mediated gene repair and protein expression.

Porcine models for studying complications and organ crosstalk in diabetes mellitus

The worldwide prevalence of diabetes mellitus and obesity is rapidly increasing not only in adults but also in children and adolescents. Diabetes is associated with macrovascular complications increasing the risk for cardiovascular disease and stroke, as well as microvascular complications leading to diabetic nephropathy, retinopathy and neuropathy. Animal models are essential for studying disease mechanisms and for developing and testing diagnostic procedures and therapeutic strategies. Rodent models are most widely used but have limitations in translational research. Porcine models have the potential to bridge the gap between basic studies and clinical trials in human patients. This article provides an overview of concepts for the development of porcine models for diabetes and obesity research, with a focus on genetically engineered models. Diabetes-associated ocular, cardiovascular and renal alterations observed in diabetic pig models are summarized and their similarities with complications in diabetic patients are discussed. Systematic multi-organ biobanking of porcine models of diabetes and obesity and molecular profiling of representative tissue samples on different levels, e.g., on the transcriptome, proteome, or metabolome level, is proposed as a strategy for discovering tissue-specific pathomechanisms and their molecular key drivers using systems biology tools. This is exemplified by a recent study providing multi-omics insights into functional changes of the liver in a transgenic pig model for insulin-deficient diabetes mellitus. Collectively, these approaches will provide a better understanding of organ crosstalk in diabetes mellitus and eventually reveal new molecular targets for the prevention, early diagnosis and treatment of diabetes mellitus and its associated complications.

Beyond classic editing: innovative CRISPR approaches for functional studies of long non-coding RNA

Long non-coding RNAs (lncRNAs) makeup a considerable part of the non-coding human genome and had been well-established as crucial players in an array of biological processes. In spite of their abundance and versatile roles, their functional characteristics remain largely undiscovered mainly due to the lack of suitable genetic manipulation tools. The emerging CRISPR/Cas9 technology has been widely adapted in several studies that aim to screen and identify novel lncRNAs as well as interrogate the functional properties of specific lncRNAs. However, the complexity of lncRNAs genes and the regulatory mechanisms that govern their transcription, as well as their unique functionality pose several limitations the utilization of classic CRISPR methods in lncRNAs functional studies. Here, we overview the unique characteristics of lncRNAs transcription and function and the suitability of the CRISPR toolbox for applications in functional characterization of lncRNAs. We discuss some of the novel variations to the classic CRISPR/Cas9 system that have been tailored and applied previously to study several aspects of lncRNAs functionality. Finally, we share perspectives on the potential applications of various CRISPR systems, including RNA-targeting, in the direct editing and manipulation of lncRNAs.

Transplacental Gene Delivery (TPGD) as a Noninvasive Tool for Fetal Gene Manipulation in Mice

Transplacental gene delivery (TPGD) is a technique for delivering nucleic acids to fetal tissues via tail-vein injections in pregnant mice. After transplacental transport, administered nucleic acids enter fetal circulation and are distributed among fetal tissues. TPGD was established in 1995 by Tsukamoto et al., and its mechanisms, and potential applications have been further characterized since. Recently, discoveries of sequence specific nucleases, such as zinc-finger nuclease (ZFN), transcription activator-like effector nucleases (TALEN), and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein-9 nuclease (Cas9) (CRISPR/Cas9), have revolutionized genome editing. In 2019, we demonstrated that intravenous injection of plasmid DNA containing CRISPR/Cas9 produced indels in fetal myocardial cells, which are comparatively amenable to transfection with exogenous DNA. In the future, this unique technique will allow manipulation of fetal cell functions in basic studies of fetal gene therapy. In this review, we describe developments of TPGD and discuss their applications to the manipulation of fetal cells.

lncRNAs: function and mechanism in cartilage development, degeneration, and regeneration

With the increasing incidence of cartilage-related diseases such as osteoarthritis (OA) and intervertebral disc degeneration (IDD), heavier financial and social burdens need to be faced. Unfortunately, there is no satisfactory clinical method to target the pathophysiology of cartilage-related diseases. Many gene expressions, signaling pathways, and biomechanical dysregulations were involved in cartilage development, degeneration, and regeneration. However, the underlying mechanism was not clearly understood. Recently, lots of long non-coding RNAs (lncRNAs) were identified in the biological processes, including cartilage development, degeneration, and regeneration. It is clear that lncRNAs were important in regulating gene expression and maintaining chondrocyte phenotypes and homeostasis. In this review, we summarize the recent researches studying lncRNAs’ expression and function in cartilage development, degeneration, and regeneration and illustrate the potential mechanism of how they act in the pathologic process. With continued efforts, regulating lncRNA expression in the cartilage regeneration may be a promising biological treatment approach.

2018 George Lyman Duff Memorial Lecture: Genetics and Genomics of Coronary Artery Disease: A Decade of Progress

Recent studies have led to a broader understanding of the genetic architecture of coronary artery disease and demonstrate that it largely derives from the cumulative effect of multiple common risk alleles individually of small effect size rather than rare variants with large effects on coronary artery disease risk. The tools applied include genome-wide association studies encompassing over 200 000 individuals complemented by bioinformatic approaches including imputation from whole-genome data sets, expression quantitative trait loci analyses, and interrogation of ENCODE (Encyclopedia of DNA Elements), Roadmap Epigenetic Project, and other data sets. Over 160 genome-wide significant loci associated with coronary artery disease risk have been identified using the genome-wide association studies approach, 90% of which are situated in intergenic regions. Here, I will describe, in part, our research over the last decade performed in collaboration with a series of bright trainees and an extensive number of groups and individuals around the world as it applies to our understanding of the genetic basis of this complex disease. These studies include computational approaches to better understand missing heritability and identify causal pathways, experimental approaches, and progress in understanding at the molecular level the function of the multiple risk loci identified and potential applications of these genomic data in clinical medicine and drug discovery.

Improvement of baculovirus as protein expression vector and as biopesticide by CRISPR/Cas9 editing

The clustered regularly interspaced short palindromic repeats (CRISPR) system-associated Cas9 endonuclease is a molecular tool that enables specific sequence editing with high efficiency. In this study, we have explored the use of CRISPR/Cas9 system for the engineering of baculovirus. We have shown that the delivering of Cas9-single guide RNA ribonucleoprotein (RNP) complex with or without DNA repair template into Sf21 insect cells through lipofection might be efficient to produce knockouts as well as knock-ins into the baculovirus. To evaluate potential application of our CRISPR/Cas9 method to improve baculovirus as protein expression vector and as biopesticide, we attempted to knockout several genes from a recombinant AcMNPV form used in the baculovirus expression system as well as in a natural occurring viral isolate from the same virus. We have additionally confirmed the adaptation of this methodology for the generation of viral knock-ins in specific regions of the viral genome. Analysis of the generated mutants revealed that the editing efficiency and the type of changes was variable but relatively high. Depending on the targeted gene, the editing rate ranged from 10% to 40%. This study established the first report revealing the potential of CRISPR/Cas9 for genome editing in baculovirus, contributing to the engineering of baculovirus as a protein expression vector as well as a biological control agent.

Triple-Targeting Delivery of CRISPR/Cas9 To Reduce the Risk of Cardiovascular Diseases

A high level of low-density lipoprotein cholesterol (LDL-C) in the blood is a major risk factor for coronary heart disease. Herein, we present a triple-targeting strategy to generate a loss-of-function mutation in Pcsk9, which regulates plasma cholesterol levels, using a nanocarrier-delivered CRISPR/Cas9 system. Nuclear localization signal (NLS)-tagged Cas9 and Pcsk9-targeted single guide RNA (sgPcsk9) were complexed with gold nanoclusters (GNCs) modified with cationic HIV-1-transactivating transcriptor (TAT) peptide and further encapsulated in a galactose-modified lipid layer to target the nanoclusters to the liver. The resulting nanoclusters had an in vitro Pcsk9-editing efficiency of about 60 % and resulting in a decrease in plasma LDL-C in mice of approximately 30%. No off-target mutagenesis was detected in 10 sites with high similarity. This approach may have therapeutic potential for the prevention and treatment of cardiovascular disease without side effects.

CRISPR-mediated gene editing for the surgeon scientist

Tremendous advances have occurred in gene editing during the past 20 years with the development of a number of systems. The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-associated protein 9 (Cas9) system represents an exciting area of research. This review examines both the relevant studies pertaining to the history, current status, and modifications of this system, in comparison with other gene-editing systems and future applications, and limitations of the CRISPR-Cas9 gene-editing system, with a focus on applications of relevance to the surgeon scientist. The CRISPR-Cas9 system was described initially in 2012 for gene editing in bacteria and then in human cells, and since then, a number of modifications have improved the efficiency and specificity of gene editing. Clinical studies have been limited because further research is required to verify its safety in patients. Some clinical trials in oncology have opened, and early studies have shown that gene editing may have a particular role in the field of organ transplantation and in the care of trauma patients. Gene editing is likely to play an important role in future research in many aspects of the surgery arena.

New personalized genetic mouse model of Lesch-Nyhan syndrome for pharmacology and gene therapy

Introduction: Lesch-Nyhan syndrome is a clinical and laboratory disorder caused by X-linked disruption of the purine metabolism. The deletion in the HPRT1 gene leads to the disappearance of valine in the eighth position of the protein amino acid sequence. The disease occurs in males and is accompanied by an excess of uric acid, urate nephropathy and neurologic impairment.

Objective of the Study: Generation of the new personalized genetic mouse model of Lesch-Nyhan syndrome for preclinical study of new approaches to the pharmacological and gene therapy

Materials and Methods: For genomic editing, the sequence was synthesized the sequence of the matrix GACCGGTCCCGTCATGCCGACACGCAGTCCCAGCGTGGTGAGCCAAGGGGACTCCAGCAGAGCCCCACAG was synthesized. For the cultivation of viable mouse embryos after microinjection, KSOM media was used. Amplification and sequencing was performed by the standard methods.

Results: A boy with not previously described hemizygous variant in the HPRT1 gene, was observed in our clinic. The mutation was the deletion of 8Val in the first exon of the HPRT1 gene. To introduce this mutation, we used the CRISPR-Cas9 genomic editing system. The genetic construct for microinjections included a mixture of the vector for the expression of Cas9 and sgRNA (px330), as well as the matrix for homologous recombination (ssODN), in a ratio of 1 part Cas9 to 3 parts of the ssODN matrix. Four of the 12 obtained animals were mosaic transgenes. One of 4 mice mated with a male from the hybrid strain CBA x C57BL/6, and descendants of F2 have already been received from this mating.

Discussion: During the creation of HPRT1 genetically modified mice, we encountered certain difficulties. First, from 615 transplanted embryos, only 12 were able to complete full embryonic development. 9 recipients we observed abortions in the later stages. These data may indicate possible violations of embryonic development in animals carrying a mutant copy of the HPRT1 gene.

Conclusion: In the current study, we present the results of the generation of a genetically modified mouse strain carrying a deletion in the HPRT1 gene. These mice can be effectively used for the preclinical testing of new drugs aimed at the treatment of Lesch-Nyhan syndrome.

Creation of Dystrophin Expressing Chimeric Cells of Myoblast Origin as a Novel Stem Cell Based Therapy for Duchenne Muscular Dystrophy

Over the past decade different stem cell (SC) based approaches were tested to treat Duchenne Muscular Dystrophy (DMD), a lethal X-linked disorder caused by mutations in dystrophin gene. Despite research efforts, there is no curative therapy for DMD. Allogeneic SC therapies aim to restore dystrophin in the affected muscles; however, they are challenged by rejection and limited engraftment. Thus, there is a need to develop new more efficacious SC therapies. Chimeric Cells (CC), created via ex vivo fusion of donor and recipient cells, represent a promising therapeutic option for tissue regeneration and Vascularized Composite Allotransplantation (VCA) due to tolerogenic properties that eliminate the need for lifelong immunosuppression. This proof of concept study tested feasibility of myoblast fusion for Dystrophin Expressing. Chimeric Cell (DEC) therapy through in vitro characterization and in vivo assessment of engraftment, survival, and efficacy in the mdx mouse model of DMD. Murine DEC were created via ex vivo fusion of normal (snj) and dystrophin–deficient (mdx) myoblasts using polyethylene glycol. Efficacy of myoblast fusion was confirmed by flow cytometry and dystrophin immunostaining, while proliferative and myogenic differentiation capacity of DEC were assessed in vitro. Therapeutic effect after DEC transplant (0.5 × 10⁶) into the gastrocnemius muscle (GM) of mdx mice was assessed by muscle functional tests. At 30 days post-transplant dystrophin expression in GM of injected mdx mice increased to 37.27 ± 12.1% and correlated with improvement of muscle strength and function. Our study confirmed feasibility and efficacy of DEC therapy and represents a novel SC based approach for treatment of muscular dystrophies.

Dystrophin Expressing Chimeric (DEC) Human Cells Provide a Potential Therapy for Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy (DMD) is a progressive and lethal disease caused by mutations of the dystrophin gene. Currently no cure exists. Stem cell therapies targeting DMD are challenged by limited engraftment and rejection despite the use of immunosuppression. There is an urgent need to introduce new stem cell-based therapies that exhibit low allogenic profiles and improved cell engraftment. In this proof-of-concept study, we develop and test a new human stem cell-based approach to increase engraftment, limit rejection, and restore dystrophin expression in the mdx/scid mouse model of DMD. We introduce two Dystrophin Expressing Chimeric (DEC) cell lines created by ex vivo fusion of human myoblasts (MB) derived from two normal donors (MB^N1/MB^N2), and normal and DMD donors (MB^N/MB^DMD). The efficacy of fusion was confirmed by flow cytometry and confocal microscopy based on donor cell fluorescent labeling (PKH26/PKH67). In vitro, DEC displayed phenotype and genotype of donor parent cells, expressed dystrophin, and maintained proliferation and myogenic differentiation. In vivo, local delivery of both DEC lines (0.5 × 10⁶) restored dystrophin expression (17.27%±8.05—MB^N1/MB^N2 and 23.79%±3.82—MB^N/MB^DMD) which correlated with significant improvement of muscle force, contraction and tolerance to fatigue at 90 days after DEC transplant to the gastrocnemius muscles (GM) of dystrophin-deficient mdx/scid mice. This study establishes DEC as a potential therapy for DMD and other types of muscular dystrophies.

Genetic Basis for Congenital Heart Disease: Revisited: A Scientific Statement From the American Heart Association

This review provides an updated summary of the state of our knowledge of the genetic contributions to the pathogenesis of congenital heart disease. Since 2007, when the initial American Heart Association scientific statement on the genetic basis of congenital heart disease was published, new genomic techniques have become widely available that have dramatically changed our understanding of the causes of congenital heart disease and, clinically, have allowed more accurate definition of the pathogeneses of congenital heart disease in patients of all ages and even prenatally. Information is presented on new molecular testing techniques and their application to congenital heart disease, both isolated and associated with other congenital anomalies or syndromes. Recent advances in the understanding of copy number variants, syndromes, RASopathies, and heterotaxy/ciliopathies are provided. Insights into new research with congenital heart disease models, including genetically manipulated animals such as mice, chicks, and zebrafish, as well as human induced pluripotent stem cell-based approaches are provided to allow an understanding of how future research breakthroughs for congenital heart disease are likely to happen. It is anticipated that this review will provide a large range of health care-related personnel, including pediatric cardiologists, pediatricians, adult cardiologists, thoracic surgeons, obstetricians, geneticists, genetic counselors, and other related clinicians, timely information on the genetic aspects of congenital heart disease. The objective is to provide a comprehensive basis for interdisciplinary care for those with congenital heart disease.

Long Noncoding RNAs and Cardiac Disease

SIGNIFICANCE

To maintain homeostasis, gene expression has to be tightly regulated by complex and multiple mechanisms occurring at the epigenetic, transcriptional, and post-transcriptional levels. One crucial regulatory component is represented by long noncoding RNAs (lncRNAs), nonprotein-coding RNA species implicated in all of these levels. Thus, lncRNAs have been associated with any given process or pathway of interest in a variety of systems, including the heart. Recent Advances: Mounting evidence implicates lncRNAs in cardiovascular diseases (CVD) and progression and their presence in the blood of heart disease patients indicates that they are attractive potential biomarkers.

CRITICAL ISSUES

Our understanding of the regulation and molecular mechanisms of action of most lncRNAs remains rudimentary. A challenge is represented by their often low evolutionary sequence conservation that limits the use of animal models for preclinical studies. Nevertheless, a growing number of lncRNAs with an impact on heart function is rapidly accumulating. In this study, we will discuss (i) lncRNAs that control heart homeostasis and disease; (ii) concepts, approaches, and methodologies necessary to study lncRNAs in the heart; and (iii) challenges posed and opportunities presented by lncRNAs as potential therapeutic targets and biomarkers.

FUTURE DIRECTIONS

A deeper knowledge of the molecular mechanisms underpinning CVDs is necessary to develop more effective treatments. Further studies are needed to clarify the regulation and function of lncRNAs in the heart before they can be considered as therapeutic targets and disease biomarkers. Antioxid. Redox Signal. 29, 880-901.

Angiogenic lncRNAs: A potential therapeutic target for ischaemic heart disease

Long noncoding RNAs (LncRNAs) are involved in biological processes and the pathology of diseases and represent an important biomarker or therapeutic target for disease. Emerging evidence has suggested that lncRNAs modulate angiogenesis by regulating the angiogenic cell process-including vascular endothelial cells (VECs); stem cells, particularly bone marrow-derived stem cells, endothelial progenitor cells (EPCs) and mesenchymal stem cells (MSCs); and vascular smooth muscle cells (VSMCs)-and participating in ischaemic heart disease (IHD). Therapeutic angiogenesis as an alternative therapy to promote coronary collateral circulation has been demonstrated to significantly improve the prognosis and quality of life of patients with IHD in past decades. Therefore, lncRNAs are likely to represent a novel therapeutic target for IHD through regulation of the angiogenesis process. This review summarizes the classification and functions of lncRNAs and their roles in regulating angiogenesis and in IHD, in the context of an overview of therapeutic angiogenesis in clinical trials.

Network-based predictions of in vivo cardiac hypertrophy

Cardiac hypertrophy is a common response of cardiac myocytes to stress and a predictor of heart failure. While in vitro cell culture studies have identified numerous molecular mechanisms driving hypertrophy, it is unclear to what extent these mechanisms can be integrated into a consistent framework predictive of in vivo phenotypes. To address this question, we investigate the degree to which an in vitro-based, manually curated computational model of the hypertrophy signaling network is able to predict in vivo hypertrophy of 52 cardiac-specific transgenic mice. After minor revisions motivated by in vivo literature, the model concordantly predicts the qualitative responses of 78% of output species and 69% of signaling intermediates within the network model. Analysis of four double-transgenic mouse models reveals that the computational model robustly predicts hypertrophic responses in mice subjected to multiple, simultaneous perturbations. Thus the model provides a framework with which to mechanistically integrate data from multiple laboratories and experimental systems to predict molecular regulation of cardiac hypertrophy.

Membrane permeabilizing amphiphilic peptide delivers recombinant transcription factor and CRISPR-Cas9/Cpf1 ribonucleoproteins in hard-to-modify cells

Delivery of recombinant proteins to therapeutic cells is limited by a lack of efficient methods. This hinders the use of transcription factors or Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) ribonucleoproteins to develop cell therapies. Here, we report a soluble peptide designed for the direct delivery of proteins to mammalian cells including human stem cells, hard-to-modify primary natural killer (NK) cells, and cancer cell models. This peptide is composed of a 6x histidine-rich domain fused to the endosomolytic peptide CM18 and the cell penetrating peptide PTD4. A less than two-minute co-incubation of 6His-CM18-PTD4 peptide with spCas9 and/or asCpf1 CRISPR ribonucleoproteins achieves robust gene editing. The same procedure, co-incubating with the transcription factor HoxB4, achieves transcriptional regulation. The broad applicability and flexibility of this DNA- and chemical-free method across different cell types, particularly hard-to-transfect cells, opens the way for a direct use of proteins for biomedical research and cell therapy manufacturing.