Gene Editing In Cells Research Articles

Human pluripotent stem cell-derived kidney organoids reveal tubular epithelial pathobiology of heterozygous HNF1B-associated dysplastic kidney malformations

Hepatocyte nuclear factor 1B (HNF1B) encodes a transcription factor expressed in developing human kidney epithelia. Heterozygous HNF1B mutations are the commonest monogenic cause of dysplastic kidney malformations (DKMs). To understand their pathobiology, we generated heterozygous HNF1B mutant kidney organoids from CRISPR-Cas9 gene-edited human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) reprogrammed from a family with HNF1B-associated DKMs. Mutant organoids contained enlarged malformed tubules displaying deregulated cell turnover. Numerous genes implicated in Mendelian kidney tubulopathies were downregulated, and mutant tubules resisted the cyclic AMP (cAMP)-mediated dilatation seen in controls. Bulk and single-cell RNA sequencing (scRNA-seq) analyses indicated abnormal Wingless/Integrated (WNT), calcium, and glutamatergic pathways, the latter hitherto unstudied in developing kidneys. Glutamate ionotropic receptor kainate type subunit 3 (GRIK3) was upregulated in malformed mutant nephron tubules and prominent in HNF1B mutant fetal human dysplastic kidney epithelia. These results reveal morphological, molecular, and physiological roles for HNF1B in human kidney tubule differentiation and morphogenesis illuminating the developmental origin of mutant-HNF1B-causing kidney disease.

Therapeutic developments for neurodegenerative GM1 gangliosidosis.

GM1 gangliosidosis (GM1) is a rare but fatal neurodegenerative disease caused by dysfunction or lack of production of lysosomal enzyme, β-galactosidase, leading to accumulation of substrates. The most promising treatments for GM1, include enzyme replacement therapy (ERT), substrate reduction therapy (SRT), stem cell therapy and gene editing. However, effectiveness is limited for neuropathic GM1 due to the restrictive nature of the blood-brain barrier (BBB). ERT and SRT alleviate substrate accumulation through exogenous supplementation over the patient's lifetime, while gene editing could be curative, fixing the causative gene, GLB1, to enable endogenous enzyme activity. Stem cell therapy can be a combination of both, with ex vivo gene editing of cells to cause the production of enzymes. These approaches require special considerations for brain delivery, which has led to novel formulations. A few therapeutic interventions have progressed to early-phase clinical trials, presenting a bright outlook for improved clinical management for GM1.

The lncRNA Malat1 is trafficked to the cytoplasm as a localized mRNA encoding a small peptide in neurons.

Synaptic function in neurons is modulated by local translation of mRNAs that are transported to distal portions of axons and dendrites. The metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is broadly expressed across cell types, almost exclusively as a nuclear long noncoding RNA. We found that in differentiating neurons, a portion of Malat1 RNA redistributes to the cytoplasm. Depletion of Malat1 using antisense oligonucleotides (ASOs) stimulates the expression of particular pre- and postsynaptic proteins, implicating Malat1 in their regulation. Neuronal Malat1 is localized in puncta of both axons and dendrites that costain with Staufen1 protein, similar to neuronal RNA granules formed by locally translated mRNAs. Ribosome profiling of cultured mouse cortical neurons identified ribosome footprints within a 5' region of Malat1 containing short open reading frames. The upstream-most reading frame (M1) of the Malat1 locus was linked to the GFP-coding sequence in mouse embryonic stem cells. When these gene-edited cells were differentiated into glutamatergic neurons, the M1-GFP fusion protein was expressed. Antibody staining for the M1 peptide confirmed its presence in wild-type neurons and showed that M1 expression was enhanced by synaptic stimulation with KCl. Our results indicate that Malat1 serves as a cytoplasmic coding RNA in the brain that is both modulated by and modulates synaptic function.

Genetic insertion of mouse Myxovirus-resistance gene 1 increases innate resistance against both high and low pathogenic avian influenza virus by significantly decreasing replication in chicken DF1 cell line

Avian influenza virus (AIV) is a constant threat to animal health with recent global outbreaks resulting in the death of hundreds of millions of birds with spillover into mammals. Myxovirus-resistance (Mx) proteins are key mediators of the antiviral response that block virus replication. Mouse (Mu) Mx (Mx1) is a strong antiviral protein that interacts with the viral nucleoprotein to inhibit polymerase function. The ability of avian Mx1 to inhibit AIV is unclear. In these studies, Mu Mx1 was stably introduced into chicken DF1 cells to enhance the immune response against AIV. Following infection, titers of AIV were significantly decreased in cells expressing Mu Mx1. In addition, considerably less cytopathic effect (CPE) and matrix protein staining was observed in gene-edited cells expressing Mu Mx1, suggesting Mu Mx1 is broadly effective against multiple AIV subtypes. This work provides foundational studies for use of gene-editing to enhance innate disease resistance against AIV.

Abstract 2634: CRISPR in vivo screen utilizing removable Cas9 system to identify epigenetic immune response modulators in antigen-sensitive mouse syngeneic models

Abstract The application of CRISPR-Cas9 screen in tumor immunology research has promoted the discovery of potential therapeutic targets and provided a deeper understanding of the mechanisms of immunotherapy resistance. Mouse syngeneic tumor model based CRISPR in vivo screen revealed significant features of immunotherapy by better approaching the tumor immune interaction. However, the immunogenicity of CRISPR-Cas9 has been widely observed in a variety of syngeneic models, which greatly limited for the application of CRISPR in vivo screen. Herein, we used two strategies for cancer cell gene editing, Cas9 protein electroporation and loxP-flanked Cas9 with Cre recombinase, to reduce the immunogenicity of CRISPR-Cas9 in CT26 subcutaneous and Renca orthotropic syngeneic models. Encouragingly, we found out that compared with constitutive Cas9-expressing All-In-One based cell pool models, both CT26 subcutaneous model and Renca orthotropic model showed a parental cell tumor comparable growth kinetics and immune checkpoint blockade ICB response by PD-1 antibody treatment. Further immuno-profiling of tumor immune microenvironment indicated limited changes from the parental cell model, which helped the data interpretation of in vivo screen outcome. We then performed a CRISPR in vivo screen by using a focused library against mouse epigenetic regulators in these two models and will discuss the hits from the screen in future. Citation Format: Yuan He, Yafei Liu, Xiao Wang, Xianyi Li, Wenle Dong, Tongrui Hao, Chenyang Zhu, Wenrong Zhou, Zhengang Peng. CRISPR in vivo screen utilizing removable Cas9 system to identify epigenetic immune response modulators in antigen-sensitive mouse syngeneic models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2634.

Novel drugs approved by the EMA, the FDA, and the MHRA in 2023: A year in review.

In 2023, seventy novel drugs received market authorization for the first time in either Europe (by the EMA and the MHRA) or in the United States (by the FDA). Confirming a steady recent trend, more than half of these drugs target rare diseases or intractable forms of cancer. Thirty drugs are categorized as "first-in-class" (FIC), illustrating the quality of research and innovation that drives new chemical entity discovery and development. We succinctly describe the mechanism of action of most of these FIC drugs and discuss the therapeutic areas covered, as well as the chemical category to which these drugs belong. The 2023 novel drug list also demonstrates an unabated emphasis on polypeptides (recombinant proteins and antibodies), Advanced Therapy Medicinal Products (gene and cell therapies) and RNA therapeutics, including the first-ever approval of a CRISPR-Cas9-based gene-editing cell therapy.

Abstract 6916: InnoPanelTMand InnoPediaTM: resources of engineered cell lines and xenografts for drug discovery

Abstract The Development of precision medicine relies on well-characterized experimental models that carry naive, induced, or engineered genomic and epigenetic features targetable by certain treatments. Patient-derived xenografts (PDX) and cell lines can serve as such in vivo and in vitro models by harboring abnormalities such as somatic and driver mutations, dysregulated gene expression and silencing, microsatellite instability, gene fusions, copy number amplification and loss of heterozygosity. In addition, cell lines can also be engineered to introduce sometimes rare-occurring abnormalities that the engineered cell line shares an identical genetic background with its parental cell line, thus providing a clearly contrasting pair to evaluate treatment specificity. With the advancement of disease research and drug discovery, existing cell lines can no longer meet the needs of various types of drug discovery. To evaluate drug efficacy more quickly and accurately, Kyinno has constructed and identified more than 4,000 engineered cell lines, including overexpressed cell lines constructed through transposon systems or lentivirus infection, gene-edited cell lines constructed through CRISPR-Cas9 technology, and reporter cell lines targeting multiple signaling pathways and membrane receptors. Besides, InnoPanelTM, a panel of over 1000 engineered cell lines was established and characterized to cover a wide range of heavily targeted genes such as CLDN18.1, CLDN18.2, LAG3, OX40, PD-L1, PD-L2, and TIM3. Cell line families were also developed for genes with multiple known driver mutations. All cell lines are annotated with background information, engineering details, functional characterization, and efficacy studies. Furthermore, we developed xenografts for several engineered cell lines and showed that the combination of cell lines and xenografts can accelerate drug development. Additionally, all of this information can be accessed in our free database, InnoPediaTM. The database also offers browsing, searching, and analytical capabilities for over 600 commonly used tumor cell lines and thousands of engineered cell lines with essential genomic and pharmacological data, cell line efficacy data for nearly 2000 common anti-tumor drugs, and comprehensive details for over 100 standard antibodies. Our engineered cell lines are now registered in the online cell line database Cellosaurus, which is available on the ExPASy server. Citation Format: Siyu Li, Chang Liu, Na Wang, Yuqing Hu, Jinying Ning, Feng Hao. InnoPanelTMand InnoPediaTM: resources of engineered cell lines and xenografts for drug discovery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6916.

Circular Single-Stranded DNA: Discovery, Biological Effects, and Applications.

The field of nucleic acid therapeutics has witnessed a significant surge in recent times, as evidenced by the increasing number of approved genetic drugs. However, current platform technologies containing plasmids, lipid nanoparticle-mRNAs, and adeno-associated virus vectors encounter various limitations and challenges. Thus, we are devoted to finding a novel nucleic acid vector and have directed our efforts toward investigating circular single-stranded DNA (CssDNA), an ancient form of nucleic acid. CssDNAs are ubiquitous, but generally ignored. Accumulating evidence suggests that CssDNAs possess exceptional properties as nucleic acid vectors, exhibiting great potential for clinical applications in genetic disorders, gene editing, and immune cell therapy. Here, we comprehensively review the discovery and biological effects of CssDNAs as well as their applications in the field of biomedical research for the first time. Undoubtedly, as an ancient form of DNA, CssDNA holds immense potential and promises novel insights for biomedical research.

Gene-edited cells: novel allogeneic gene/cell therapy for epidermolysis bullosa.

Epidermolysis bullosa (EB) is a group of rare genetic skin fragility disorders, which are hereditary. These disorders are associated with mutations in at least 16 genes that encode components of the epidermal adhesion complex. Currently, there are no effective treatments for this disorder. All current treatment approaches focus on topical treatments to prevent complications and infections. In recent years, significant progress has been achieved in the treatment of the severe genetic skin blistering condition known as EB through preclinical and clinical advancements. Promising developments have emerged in the areas of protein and cell therapies, such as allogeneic stem cell transplantation; in addition, RNA-based therapies and gene therapy approaches have also become a reality. Stem cells obtained from embryonic or adult tissues, including the skin, are undifferentiated cells with the ability to generate, maintain, and replace fully developed cells and tissues. Recent advancements in preclinical and clinical research have significantly enhanced stem cell therapy, presenting a promising treatment option for various diseases that are not effectively addressed by current medical treatments. Different types of stem cells such as primarily hematopoietic and mesenchymal, obtained from the patient or from a donor, have been utilized to treat severe forms of diseases, each with some beneficial effects. In addition, extensive research has shown that gene transfer methods targeting allogeneic and autologous epidermal stem cells to replace or correct the defective gene are promising. These methods can regenerate and restore the adhesion of primary keratinocytes in EB patients. The long-term treatment of skin lesions in a small number of patients has shown promising results through the transplantation of skin grafts produced from gene-corrected autologous epidermal stem cells. This article attempts to summarize the current situation, potential development prospects, and some of the challenges related to the cell therapy approach for EB treatment.

The NF-κB RelA transcription factor is not required for CD8+ T-cell function in acute viral infection and cancer.

CD8+ T cells are critical mediators of pathogen clearance and anti-tumor immunity. Although signaling pathways leading to the activation of NF-κB transcription factors have crucial functions in the regulation of immune responses, the CD8+ T cell-autonomous roles of the different NF-κB subunits, are still unresolved. Here, we investigated the function of the ubiquitously expressed transcription factor RelA in CD8+ T-cell biology using a novel mouse model and gene-edited human cells. We found that CD8+ T cell-specific ablation of RelA markedly altered the transcriptome of ex vivo stimulated cells, but maintained the proliferative capacity of both mouse and human cells. In contrast, in vivo experiments showed that RelA deficiency did not affect the CD8+ T-cell response to acute viral infection or transplanted tumors. Our data suggest that in CD8+ T cells, RelA is dispensable for their protective activity in pathological contexts.

The History, Use, and Challenges of Therapeutic Somatic Cell and Germline Gene Editing

ABSTRACT Gene editing is a technology that has been rapidly developing and that has many applications as well as ethical and practical implications. This article is a review that outlines the history of current technology, as well as the advantages and challenges in use for somatic cell and germline gene editing. Clustered regularly interspaced short palindromic repeat (CRISPR) was first introduced in 2002 and initially saw limited use among researchers. However, in 2012, it was discovered that a nuclease associated with CRISPR (Cas9) could be used with guide RNA to cleave double-stranded DNA in specific places, raising the potential for targeted gene editing. Immediately, the scientific community saw endless possibilities of this technology for clinical therapies and treatment of genetic disorders. Currently, more than 110 gene editing–based therapies are in clinical trials, with 2 different treatments already in phase 3 clinical trials. To date, all gene editing therapies that have progressed to clinical trials are somatic cell editing therapies. Germline gene editing, in which changes to genes can be passed to the next generation, is attractive for inherited diseases but has many ethical considerations and challenges that must be addressed before this technology is further developed. One concern is off-target editing events that could involve DNA sequences with high similarity to the target sequence. In addition to this, DNA breaks from Cas9 can result in chromosomal instability and possible abnormalities such as large deletions, translocations, and rearrangements. This could be problematic particularly in germline editing, where the effects are passed down to the next generation. Gene editing does, however, have great potential. Somatic cell gene editing has been successfully used to prevent and treat disease. One advantage of somatic cells is that they can be removed, edited, and returned to the patient to proliferate normally. For the therapies currently in stage 3 clinical trials, there have been few instances of failure to modify the alleles and no evidence of off-target editing using this method. Somatic cell gene editing has successfully been used in animal models and in limited human trials to treat diseases with easily accessible in vivo sites, such as the eye. Germline gene editing has advantages over somatic cell gene editing, as therapies can be developed to permanently correct heritable genetic diseases. It could also be adapted easily during an in vitro fertilization process for parents who are carriers of 1 or more diseases to eliminate the risk of their offspring manifesting the disease. However, germline editing creates changes to the DNA that is then passed to offspring, raising ethical and safety concerns. Many trials in animal models as well as early human clinical trials show promise for these treatments, but challenges remain including costs and logistical considerations such as time, space, and expertise. Another challenge is that because these therapies are targeted, each variation of each disease must be treated differently, with a therapy developed specifically for each disease and potentially even variations of the same disease. This again represents significant challenges related to cost, time, and expertise. Ethical challenges for germline gene editing include the use of human embryos, high rates of off-target editing, and possible severe chromosomal deletions depending on the target. Large chromosomal rearrangements, as required with attempting to eradicate certain diseases, have been recently shown to be more difficult and dangerous than smaller rearrangements. This presents a unique challenge that must be overcome before implementing this technique in any therapies. There are many possibilities and exciting opportunities with gene editing therapies, some of which are closer to fruition than others. We are potentially close to implementing some therapies, such as those for sickle cell disease, while farther from broad use for other therapies. The pace at which this technology has developed is astounding, which brings hope that this research will continue to progress quickly, and we may be closer than we think to effectively treating genetic disease with gene editing technology.

Multichannel-optical imaging for in vivo evaluating the safety and therapeutic efficacy of stem cells in tumor model in terms of cell tropism, proliferation and NF-κB activity

Stem cell-based cancer treatment has garnered significant attention, yet its safety and efficacy remain incompletely understood. The nuclear factor-kappa B (NF-κB) pathway, a critical signaling mechanism involved in tumor growth, angiogenesis, and invasion, serves as an essential metric for evaluating the behavior of stem cells in tumor models. Herein, we report the development of a triple-channel imaging system capable of simultaneously monitoring the tropism of stem cells towards tumors, assessing tumor proliferation, and quantifying tumor NF-κB activity. In this system, we generated a CRISPR-Cas9 gene-edited human glioblastoma cell line, GE-U87-MG, which provided a reliable readout of the proliferation and NF-κB activity of tumors by EF1α-RFLuc- and NF-κB-GLuc-based bioluminescent imaging, respectively. Additionally, near infrared-II emitting Tat-PEG-AgAuSe quantum dots were developed for tracking of stem cell tropism towards tumor. In a representative case involving human mesenchymal stem cells (hMSCs), multichannel imaging revealed no discernible effect of hMSCs on the proliferation and NF-κB activity of GE-U87-MG tumors. Moreover, hMSCs engineered to overexpress the necrosis factor-related apoptosis-inducing ligand were able to inhibit NF-κB activity and growth of GE-U87-MG in vivo. Taken together, our imaging system represents a powerful and feasible approach to evaluating the safety and therapeutic efficacy of stem cells in tumor models.

Abstract A063: CancerTools.org: Research Tools Supporting Breast Cancer Studies

Abstract CancerTools.org is the latest, non-profit cancer-focused biorepository. Driven by a mission to accelerate cancer research discoveries, the platform allows scientists to deposit and access tangible laboratory research materials. Till date, researchers from over 175 academic institutes globally have already deposited their tools, generating a cutting-edge portfolio of over 5,000 reagents, including a range of cell-based models and antibodies. Breast cancer is one of the most frequent malignancies in women worldwide. A comprehensive collection of tools has been curated at CancerTools.org to support this important area of research. Cell-based models include the RMAM007-3 breast cancer organoid which recapitulates in vivo tumour characteristics and is suitable for disease modelling, 3D imaging, and anticancer drug discovery. Cell lines such as human anti-oestrogen resistant lines developed from MCF-7 and T47D cells, demonstrate resistance to hormone-dependent treatments and are useful for studying therapy resistance mechanisms and biomarker development for breast cancer detection. NCI-HPN-F murine cell lines with recurrent chromosomal aneuploidies, have enabled investigation and identification of tumorigenesis related cancer-specific genes and signalling pathways. Further models include gene-edited cell lines to explore BRCA1 hypermethylation pathways; reporter breast cancer cell lines to assess apoptosis, necrosis, and autophagy; and immortalised human breast epithelial cell lines to study differentiation and phenotypic transformation. To provide a physiologically relevant cell culture environment, PlasmaxTM, a defined media that mirrors the concentration of over 50 components to human plasma, is also part of the repertoire. It has been used to culture triple-negative breast cancer cell lines to recapitulate the tumour metabolic environment. Antibodies to study breast cancer biology, including tumour suppressors, angiogenesis and metastasis, form part of the portfolio. Antibodies targeting tumour suppressors include RB1, which is often lost by mutation, deletion, transcriptional silencing and hyper-phosphorylation in malignancies- including breast cancer. Deletion and rearrangement of RB1 is estimated in ~20-25% of breast cancer cell lines. Tools identifying specific RB1 phosphorylation sites, include Anti-Phospho-Rb for Ser608 and Thr356. Additional insights into breast cancer prognosis are offered by Anti-Maspin [16F7] which recognises wildtype and denaturated forms of the protein. Maspin is an inhibitor of serine proteases with tumour suppressor activity in breast cancer. Its nuclear staining associates with favourable outcomes in contrast to cytoplasmic staining. MUC1 is also aberrantly overexpressed in 90% of human breast cancer, thus, representing a promising marker for breast cancer diagnosis and prognosis. Further research support is offered by an extensive range of antibodies for MUC1’s different isoforms. Visit our stand to explore more about depositing and accessing tools and technologies that support breast cancer research. Citation Format: Vera Moiseeva, Sara Omenetti, Abby Henney, Katie Valencia. CancerTools.org: Research Tools Supporting Breast Cancer Studies [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr A063.

What a Clinician Needs to Know About Genome Editing: Status and Opportunities for Inborn Errors of Immunity

During the past twenty years, gene editing has emerged as a novel form of gene therapy. Since the publication of the first potentially therapeutic gene editing platform for genetic disorders, increasingly sophisticated editing technologies have been developed. As with viral vector mediated gene addition, inborn errors of immunity (IEIs) are excellent candidate diseases for a corrective autologous haematopoietic stem cell gene editing strategy. Research on gene editing for IEIs is still entirely preclinical, with no trials yet underway. However, with editing techniques maturing, scientists are investigating this novel form of gene therapy in context of an increasing number of IEIs. Here, we present an overview of these studies and the recent progress moving these technologies closer to clinical benefit.

Generation of a gene-edited H9 embryonic stem cell line carrying a DOX-inducible NGN2 expression cassette in the CLYBL locus

The pro-neural transcription factor neurogenin-2 (NGN2) possesses the ability to rapidly and effectively transform stem cells into fully operational neurons. Here we report the successful generation of a modified H9 human embryonic H9 stem cell line containing a doxycycline (DOX) inducible NGN2 expression construct featuring a floxed Blasticidin/mApple selection module in the safe-harbor locus CLYBL. This cell line retains its pluripotent state in the absence of DOX, yet readily transitions into a neuronal state upon DOX introduction.

Gene-editing sickle cell drug not approved for NHS use in draft NICE guidance

Gene-editing sickle cell drug not approved for NHS use in draft NICE guidance

Efficient Gene-Editing in Human Pluripotent Stem Cells Through Simplified Assembly of Adeno-Associated Viral (AAV) Donor Templates.

Gene-edited human pluripotent stem cells provide attractive model systems to functionally interrogate the role of specific genetic variants in relevant cell types. However, the need to isolate and screen edited clones often remains a bottleneck, in particular when recombination rates are sub-optimal. Here, we present a protocol for flexible gene editing combining Cas9 ribonucleoprotein with donor templates delivered by adeno-associated virus (AAV) vectors to yield high rates of homologous recombination. To streamline the workflow, we designed a modular system for one-step assembly of targeting vectors based on Golden Gate cloning and developed a rapid protocol for small-scale isolation of AAV virions of serotype DJ. High homology-directed repair (HDR) rates in human pluripotent stem cells (hPSCs), ~70% in ACTB and ~30% in LMNB1, were achieved using this approach, also with short (300 bp) homology arms. The modular design of donor templates is flexible and allows for the generation of conditional and/or complex alleles. This protocol thus provides a flexible and efficient strategy workflow to rapidly generate gene-edited hPSC lines. Key features • Versatile approach combining AAV-DJ donors and CRISPR ribonucleoproteins, providing an efficient method for long and short edits, insertions, and deletions in human pluripotent stem cells. • One-step cloning method for rapid generation of customized AAV donor plasmids. • Simplified AAV purification pipeline for ready-to-infect virion preparations.

Mutations in DNAJC19 cause altered mitochondrial structure and increased mitochondrial respiration in human iPSC-derived cardiomyocytes

BackgroundDilated cardiomyopathy with ataxia (DCMA) is an autosomal recessive disorder arising from truncating mutations in DNAJC19, which encodes an inner mitochondrial membrane protein. Clinical features include an early onset, often life-threatening, cardiomyopathy associated with other metabolic features. Here, we aim to understand the metabolic and pathophysiological mechanisms of mutant DNAJC19 for the development of cardiomyopathy. MethodsWe generated induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) of two affected siblings with DCMA and a gene-edited truncation variant (tv) of DNAJC19 which all lack the conserved DnaJ interaction domain. The mutant iPSC-CMs and their respective control cells were subjected to various analyses, including assessments of morphology, metabolic function, and physiological consequences such as Ca2+ kinetics, contractility, and arrhythmic potential. Validation of respiration analysis was done in a gene-edited HeLa cell line (DNAJC19tvHeLa). ResultsStructural analyses revealed mitochondrial fragmentation and abnormal cristae formation associated with an overall reduced mitochondrial protein expression in mutant iPSC-CMs. Morphological alterations were associated with higher oxygen consumption rates (OCRs) in all three mutant iPSC-CMs, indicating higher electron transport chain activity to meet cellular ATP demands. Additionally, increased extracellular acidification rates suggested an increase in overall metabolic flux, while radioactive tracer uptake studies revealed decreased fatty acid uptake and utilization of glucose. Mutant iPSC-CMs also showed increased reactive oxygen species (ROS) and an elevated mitochondrial membrane potential. Increased mitochondrial respiration with pyruvate and malate as substrates was observed in mutant DNAJC19tv HeLa cells in addition to an upregulation of respiratory chain complexes, while cellular ATP-levels remain the same. Moreover, mitochondrial alterations were associated with increased beating frequencies, elevated diastolic Ca2+ concentrations, reduced sarcomere shortening and an increased beat-to-beat rate variability in mutant cell lines in response to β-adrenergic stimulation. ConclusionsLoss of the DnaJ domain disturbs cardiac mitochondrial structure with abnormal cristae formation and leads to mitochondrial dysfunction, suggesting that DNAJC19 plays an essential role in mitochondrial morphogenesis and biogenesis. Moreover, increased mitochondrial respiration, altered substrate utilization, increased ROS production and abnormal Ca2+ kinetics provide insights into the pathogenesis of DCMA-related cardiomyopathy.

Developing Topics.

Goal 1 of the National Plan to Address Alzheimer's Disease (AD) is to prevent and effectively treat AD and AD-related dementias (ADRD) by 2025. Toward this goal, NINDS plans 14 ADRD funding opportunities for 2024 to support training, basic mechanisms, translational, and clinical research for ADRD. Here, we describe ADRD translational therapy development initiatives, which include 1) multi-target validation, 2) early-stage therapy development, 3) genome editing and 4) animal model development and validation. Note, ADRD specific funding opportunities are not required. ADRD researchers can also take advantage of NINDS existing programs such as the NIH Blueprint for Neurotherapeutics (BPN) for Small Molecule or Biologic therapy development. These programs support optimization, manufacture, IND-enabling studies and first in human clinical trials through a combination of grants and complementary access to NIH-provided CROs and consultants. All concepts discussed here are approved, however NIH cannot guarantee future funding opportunities, award mechanisms, or funding allocation. A funding opportunity is only official when published in the NIH Guide. Multi-Target Validation for ADRD concept has the goal to support research that would validate multiple targets for future therapy development that better reflect the complexity of disease. Early-Stage Therapy Development concept would support the development of small molecule or biologic therapeutics and would be a reissue of RFA-NS-22-059, which supported assay development, therapeutic screening, optimization, and in vivo efficacy work in preparation for later-stage programs. Genome Editing for ADRD concept would support early translational research focused on somatic cell gene editing with the expectation that studies will address feasibility of the gene editing approach and would be a reissue of RFA-NS-23-017. PAR-23-154 "Development and Validation of Models for Alzheimer's Disease-Related Dementias (ADRD)" supports the development and validation of clinically- and pathophysiologically-relevant models of ADRD that can be used for future therapy development. Models should reflect multiple aspects of the human condition and include internal, face, construct, and predictive validation to the extent possible. Through these initiatives, NINDS hopes to provide a comprehensive pipeline for ADRD therapy development from target validation to the clinic.

Germline PTEN genotype-dependent phenotypic divergence during the early neural developmental process of forebrain organoids.

PTEN germline mutations account for ~0.2-1% of all autism spectrum disorder (ASD) cases, as well as ~17% of ASD patients with macrocephaly, making it one of the top ASD-associated risk genes. Individuals with germline PTEN mutations receive the molecular diagnosis of PTEN Hamartoma Tumor Syndrome (PHTS), an inherited cancer predisposition syndrome, about 20-23% of whom are diagnosed with ASD. We generated forebrain organoid cultures from gene-edited isogenic human induced pluripotent stem cells (hiPSCs) harboring a PTENG132D (ASD) or PTENM134R (cancer) mutant allele to model how these mutations interrupt neurodevelopmental processes. Here, we show that the PTENG132D allele disrupts early neuroectoderm formation during the first several days of organoid generation, andresults in deficient electrophysiology. While organoids generated from PTENM134R hiPSCs remained morphologically similar to wild-type organoids during this early stage in development, we observed disrupted neuronal differentiation, radial glia positioning, and cortical layering in both PTEN-mutant organoids at the later stage of 72+ days of development. Perifosine, an AKT inhibitor, reduced over-activated AKT and partially corrected the abnormalities in cellular organization observed in PTENG132D organoids. Single cell RNAseq analyses on early-stage organoids revealed that genes related to neural cell fate were decreased in PTENG132D mutant organoids, and AKT inhibition was capable of upregulating gene signatures related to neuronal cell fate and CNS maturation pathways. These findings demonstrate that different PTEN missense mutations can have a profound impact on neurodevelopment at diverse stages which in turn may predispose PHTS individuals to ASD. Further study will shed light on ways to mitigate pathological impact of PTEN mutants on neurodevelopment by stage-specific manipulation of downstream PTEN signaling components.