Reprogramming MHC specificity by CRISPR-Cas9-assisted cassette exchange

A structural peculiarity of Antarctic fish IgM drives the generation of an engineered mAb by CRISPR/Cas9

IgM is the major circulating Ig isotype in teleost fish, showing in Antarctic fish unique features such as an extraordinary long hinge region, which plays a crucial role in antibody structure and function. In this work, we describe the replacement of the hinge region of a murine monoclonal antibody (mAb) with the peculiar hinge from Antarctic fish IgM. We use the CRISPR/Cas9 system as a powerful tool for generating the engineered mAb. Then, we assessed its functionality by using an innovative plasmonic substrate based on bimetallic nanoislands (AgAuNIs). The affinity constant of the modified mAb was 2.5-fold higher than that obtained from wild-type mAb against the specific antigen. Here, we show the suitability of the CRISPR/Cas9 method for modifying a precise region in immunoglobulin gene loci. The overall results could open a frontier in further structural modifications of mAbs for biomedical and diagnostic purposes.

Chemical and biological characterization of vaccine adjuvant QS-21 produced via plant cell culture

Many vaccines, including those using recombinant antigen subunits, rely on adjuvant(s) to enhance the efficacy of the host immune responses. Among the few adjuvants clinically approved, QS-21, a saponin-based immunomodulatory molecule isolated from the tree bark of Quillaja saponaria (QS) is used in complex formulations in approved effective vaccines. High demand of the QS raw material as well as manufacturing scalability limitation has been barriers here. We report for the first-time successful plant cell culture production of QS-21 having structural, chemical, and biologic, properties similar to the bark extracted product. These data ensure QS-21 and related saponins are broadly available and accessible to drug developers.

An efficient and cost-effective method for disrupting genes in RAW264.7 macrophages using CRISPR-Cas9

The clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) are widely used for genome editing in cultured cell lines. However, the implementation of genome editing is still challenging due to the complex and often costly multi-step process associated with this technique. Moreover, the efficiency of genome editing varies across cell types, often limiting utility. Herein, we describe pCRISPR-EASY, a vector for simplified cloning of single guide RNAs (sgRNAs) and its simultaneous introduction with CRISPR-Cas9 into cultured cells using a non-viral delivery system. We outline a comprehensive, step-by-step protocol for genome editing in RAW264.7 macrophages, a mouse macrophage cell line widely used in biomedical research for which genome editing using CRISPR-Cas9 has been restricted to lentiviral or expensive commercial reagents. This provides an economical, highly efficient and reliable method for genome editing that can easily be adapted for use in other systems.

GMP-manufactured CRISPR/Cas9 technology as an advantageous tool to support cancer immunotherapy

BACKGROUND

CRISPR/Cas9 system to treat human-related diseases has achieved significant results and, even if its potential application in cancer research is improving, the application of this approach in clinical practice is still a nascent technology.

MAIN BODY

CRISPR/Cas9 technology is not yet used as a single therapy to treat tumors but it can be combined with traditional treatment strategies to provide personalized gene therapy for patients. The combination with chemotherapy, radiation and immunotherapy has been proven to be a powerful means of screening, identifying, validating and correcting tumor targets. Recently, CRISPR/Cas9 technology and CAR T-cell therapies have been integrated to open novel opportunities for the production of more efficient CAR T-cells for all patients. GMP-compatible equipment and reagents are already available for several clinical-grade systems at present, creating the basis and framework for the accelerated development of novel treatment methods.

CONCLUSION

Here we will provide a comprehensive collection of the actual GMP-grade CRISPR/Cas9-mediated approaches used to support cancer therapy highlighting how this technology is opening new opportunities for treating tumors.

Challenges in the clinical advancement of cell therapies for Parkinson's disease

Cell therapies as potential treatments for Parkinson's disease first gained traction in the 1980s, owing to the clinical success of trials that used transplants of foetal midbrain dopaminergic tissue. However, the poor standardization of the tissue for grafting, and constraints on its availability and ethical use, have hindered this treatment strategy. Recent advances in stem-cell technologies and in the understanding of the development of dopaminergic neurons have enabled preclinical advancements of promising stem-cell therapies. To move these therapies to the clinic, appropriate levels of safety screening, as well as optimization of the cell products and the scalability of their manufacturing, will be required. In this Review, we discuss how challenges pertaining to cell sources, functional and safety testing, manufacturing and storage, and clinical-trial design are being addressed to advance the translational and clinical development of cell therapies for Parkinson's disease.

Recent advances and applications of CRISPR-Cas9 in cancer immunotherapy

The incidence and mortality of cancer are the major health issue worldwide. Apart from the treatments developed to date, the unsatisfactory therapeutic effects of cancers have not been addressed by broadening the toolbox. The advent of immunotherapy has ushered in a new era in the treatments of solid tumors, but remains limited and requires breaking adverse effects. Meanwhile, the development of advanced technologies can be further boosted by gene analysis and manipulation at the molecular level. The advent of cutting-edge genome editing technology, especially clustered regularly interspaced short palindromic repeats (CRISPR-Cas9), has demonstrated its potential to break the limits of immunotherapy in cancers. In this review, the mechanism of CRISPR-Cas9-mediated genome editing and a powerful CRISPR toolbox are introduced. Furthermore, we focus on reviewing the impact of CRISPR-induced double-strand breaks (DSBs) on cancer immunotherapy (knockout or knockin). Finally, we discuss the CRISPR-Cas9-based genome-wide screening for target identification, emphasis the potential of spatial CRISPR genomics, and present the comprehensive application and challenges in basic research, translational medicine and clinics of CRISPR-Cas9.

A small molecule redistributes iron in ferroportin-deficient mice and patient-derived primary macrophages

Iron misdistribution underlies various diseases, ranging from anemia to neurodegeneration, but approaches to addressing this general problem are lacking. We recently reported that a small molecule natural product, hinokitiol, is capable of restoring hemoglobinization in various animal models with missing iron transporters. We now show that hinokitiol is capable of redistributing iron systemically, which in turn restores iron homeostasis in ferroportin-deficient mice and in primary macrophages derived from patients with ferroportin disease. We also elucidated the stepwise mechanism of hinokitiol-mediated iron redistribution and physiological restoration. Together, these results provide foundational support for using a molecular prosthetics approach for better understanding and possibly treating iron misdistribution.

Deficiencies of the transmembrane iron-transporting protein ferroportin (FPN1) cause the iron misdistribution that underlies ferroportin disease, anemia of inflammation, and several other human diseases and conditions. A small molecule natural product, hinokitiol, was recently shown to serve as a surrogate transmembrane iron transporter that can restore hemoglobinization in zebrafish deficient in other iron transporting proteins and can increase gut iron absorption in FPN1-deficient flatiron mice. However, whether hinokitiol can restore normal iron physiology in FPN1-deficient animals or primary cells from patients and the mechanisms underlying such targeted activities remain unknown. Here, we show that hinokitiol redistributes iron from the liver to red blood cells in flatiron mice, thereby increasing hemoglobin and hematocrit. Mechanistic studies confirm that hinokitiol functions as a surrogate transmembrane iron transporter to release iron trapped within liver macrophages, that hinokitiol-Fe complexes transfer iron to transferrin, and that the resulting transferrin-Fe complexes drive red blood cell maturation in a transferrin-receptor–dependent manner. We also show in FPN1-deficient primary macrophages derived from patients with ferroportin disease that hinokitiol moves labile iron from inside to outside cells and decreases intracellular ferritin levels. The mobilization of nonlabile iron is accompanied by reductions in intracellular ferritin, consistent with the activation of regulated ferritin proteolysis. These findings collectively provide foundational support for the translation of small molecule iron transporters into therapies for human diseases caused by iron misdistribution.

Lure-and-kill macrophage nanoparticles alleviate the severity of experimental acute pancreatitis

Acute pancreatitis is a disease associated with suffering and high lethality. Although the disease mechanism is unclear, phospholipase A2 (PLA2) produced by pancreatic acinar cells is a known pathogenic trigger. Here, we show macrophage membrane-coated nanoparticles with a built-in 'lure and kill' mechanism (denoted 'MΦ-NP(L&K)') for the treatment of acute pancreatitis. MΦ-NP(L&K) are made with polymeric cores wrapped with natural macrophage membrane doped with melittin and MJ-33. The membrane incorporated melittin and MJ-33 function as a PLA2 attractant and a PLA2 inhibitor, respectively. These molecules, together with membrane lipids, work synergistically to lure and kill PLA2 enzymes. These nanoparticles can neutralize PLA2 activity in the sera of mice and human patients with acute pancreatitis in a dose-dependent manner and suppress PLA2-induced inflammatory response accordingly. In mouse models of both mild and severe acute pancreatitis, MΦ-NP(L&K) confer effective protection against disease-associated inflammation, tissue damage and lethality. Overall, this biomimetic nanotherapeutic strategy offers an anti-PLA2 treatment option that might be applicable to a wide range of PLA2-mediated inflammatory disorders.

Molecular Design, Optimization, and Genomic Integration of Chimeric B Cell Receptors in Murine B Cells

Immune cell therapies based on the integration of synthetic antigen receptors comprise a powerful strategy for the treatment of diverse diseases, most notably T cells engineered to express chimeric antigen receptors (CAR) for targeted cancer therapy. In addition to T lymphocytes, B lymphocytes may also represent valuable immune cells that can be engineered for therapeutic purposes such as protein replacement therapy or recombinant antibody production. In this article, we report a promising concept for the molecular design, optimization, and genomic integration of a novel class of synthetic antigen receptors, chimeric B cell receptors (CBCR). We initially optimized CBCR expression and detection by modifying the extracellular surface tag, the transmembrane regions and intracellular signaling domains. For this purpose, we stably integrated a series of CBCR variants using CRISPR-Cas9 into immortalized B cell hybridomas. Subsequently, we developed a reliable and consistent pipeline to precisely introduce cassettes of several kb size into the genome of primary murine B cells also using CRISPR-Cas9 induced HDR. Finally, we were able to show the robust surface expression and antigen recognition of a synthetic CBCR in primary B cells. We anticipate CBCRs and our approach for engineering primary B cells will be a valuable tool for the advancement of future B cell- based immune cell therapies.

The application of CRISPR-Cas9 genome editing tool in cancer immunotherapy

Clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (CRISPR-Cas9) system was originally discovered in prokaryotes functioned as a part of the adaptive immune system. Because of its high efficiency and easy operability, CRISPR-Cas9 system has been developed to be a powerful and versatile gene editing tool shortly after its discovery. Given that multiple genetic alterations are the main factors that drive genesis and development of tumor, CRISPR-Cas9 system has been applied to correct cancer-causing gene mutations and deletions and to engineer immune cells, such as chimeric antigen receptor T (CAR T) cells, for cancer immunotherapeutic applications. Recently, CRISPR-Cas9-based CAR T-cell preparation has been an important breakthrough in antitumor therapy. Here, we summarize the mechanism, delivery and the application of CRISPR-Cas9 in gene editing, and discuss the challenges and future directions of CRISPR-Cas9 in cancer immunotherapy.

Multiple Knockout of Classical HLA Class II β-Chains by CRISPR/Cas9 Genome Editing Driven by a Single Guide RNA

Comprehensive knockout of HLA class II (HLA-II) β-chain genes is complicated by their high polymorphism. In this study, we developed CRISPR/Cas9 genome editing to simultaneously target HLA-DRB, -DQB1, and -DPB1 through a single guide RNA recognizing a conserved region in exon 2. Abrogation of HLA-II surface expression was achieved in five different HLA-typed, human EBV-transformed B lymphoblastoid cell lines (BLCLs). Next-generation sequencing-based detection confirmed specific genomic insertion/deletion mutations with 99.5% penetrance in sorted cells for all three loci. No alterations were observed in HLA-I genes, the HLA-II peptide editor HLA-DMB, or its antagonist HLA-DOB, showing high on-target specificity. Transfection of full-length HLA-DPB1 mRNA into knockout BLCLs fully restored HLA-DP surface expression and recognition by alloreactive human CD4 T cells. The possibility to generate single HLA-II-expressing BLCLs by one-shot genome editing opens unprecedented opportunities for mechanistically dissecting the interaction of individual HLA variants with the immune system.

Development of immunocompatible pluripotent stem cells via CRISPR-based human leukocyte antigen engineering

Pluripotent stem cell transplantation is a promising regenerative strategy for treating intractable diseases. However, securing human leukocyte antigen (HLA)-matched donor stem cells is extremely difficult. The traditional approach for generating such cells is to establish homozygous pluripotent stem cell lines. Unfortunately, because of HLA diversity, this strategy is too time-consuming to be of practical use. HLA engineering of donor stem cells has been proposed recently as a means to evade graft-versus-host rejection in stem cell allotransplantation. This approach would be advantageous in both time and cost to the traditional method, but its feasibility must be investigated. In this study, we used CRISPR/Cas9 to knockout HLA-B from inducible pluripotent stem cells (iPSCs) with heterogenous HLA-B and showed that the HLA-B knockout iPSCs resulted in less immunogenicity in HLA-B antisera than that in the control. Our results support the feasibility of HLA-engineered iPSCs in stem cell allotransplantation.

Blocking the expression of genes that regulate the immune response in therapeutic stem cells could increase the chances of success following transplantation. Discrepancies between human leukocyte antigen (HLA) genes in a patient and those in transplanted stem cells can cause a damaging immune response and transplantation failure, yet matching HLA types between donors and recipients is notoriously difficult. Ji Hyeon Ju at The Catholic University of Korea in Seoul and colleagues have used the CRISPR/Cas9 gene editing system to introduce a mutation in the HLA-B gene that prevents its expression in pluripotent stem cells derived from adult cells. These modified cells not only retain their capacity to self-renew and differentiate, they are also less likely to trigger an immune response. This promising new approach could reduce the time and cost of developing effective stem cell therapies.

Blood-Brain Barrier: From Physiology to Disease and Back

The blood-brain barrier (BBB) prevents neurotoxic plasma components, blood cells, and pathogens from entering the brain. At the same time, the BBB regulates transport of molecules into and out of the central nervous system (CNS), which maintains tightly controlled chemical composition of the neuronal milieu that is required for proper neuronal functioning. In this review, we first examine molecular and cellular mechanisms underlying the establishment of the BBB. Then, we focus on BBB transport physiology, endothelial and pericyte transporters, and perivascular and paravascular transport. Next, we discuss rare human monogenic neurological disorders with the primary genetic defect in BBB-associated cells demonstrating the link between BBB breakdown and neurodegeneration. Then, we review the effects of genes underlying inheritance and/or increased susceptibility for Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease, and amyotrophic lateral sclerosis (ALS) on BBB in relation to other pathologies and neurological deficits. We next examine how BBB dysfunction relates to neurological deficits and other pathologies in the majority of sporadic AD, PD, and ALS cases, multiple sclerosis, other neurodegenerative disorders, and acute CNS disorders such as stroke, traumatic brain injury, spinal cord injury, and epilepsy. Lastly, we discuss BBB-based therapeutic opportunities. We conclude with lessons learned and future directions, with emphasis on technological advances to investigate the BBB functions in the living human brain, and at the molecular and cellular level, and address key unanswered questions.

Applications of CRISPR-Cas in Bioengineering, Biotechnology, and Translational Research

CRISPR technology is rapidly evolving, and the scope of CRISPR applications is constantly expanding. CRISPR was originally employed for genome editing. Its application was then extended to epigenome editing, karyotype engineering, chromatin imaging, transcriptome, and metabolic pathway engineering. Now, CRISPR technology is being harnessed for genetic circuits engineering, cell signaling sensing, cellular events recording, lineage information reconstruction, gene drive, DNA genotyping, miRNA quantification, in vivo cloning, site-directed mutagenesis, genomic diversification, and proteomic analysis in situ. It has also been implemented in the translational research of human diseases such as cancer immunotherapy, antiviral therapy, bacteriophage therapy, cancer diagnosis, pathogen screening, microbiota remodeling, stem-cell reprogramming, immunogenomic engineering, vaccine development, and antibody production. This review aims to summarize the key concepts of these CRISPR applications in order to capture the current state of play in this fast-moving field. The key mechanisms, strategies, and design principles for each technological advance are also highlighted.

Novel therapies for alopecia areata: The era of rational drug development

Treatments for alopecia areata (AA) have evolved over the decades from broad and nonspecific therapies to those that are now more targeted and rationally selected. This was achieved by means of close cooperation and communication between clinicians and basic scientists, which resulted in the elucidation and understanding of the unique pathophysiology of AA. In this review we discuss this evolution and how novel therapies for AA have changed over the decades, what we have in our current arsenal of drugs for this potentially devastating disease, and what the future holds.