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Generalizable and Non-genetic Approach to Create Metabolically-active-but-non-replicating Bacteria

Researchers at the University of California, Davis have developed a method to stop bacterial growth while maintaining desirable metabolic functions for therapeutic and biotechnological applications.

A Broadly Neutralizing Molecule Against Clostridium Difficile Toxin B

Researchers at UCI have developed a family of recombinant protein therapeutics against Clostridium difficile designed to provide broad-spectrum protection and neutralization against all isoforms of its main toxin, TcdB. These antitoxin molecules feature fragments of TcdB’s human receptors (CSPG4 and FZD) which compete for TcdB binding, significantly improving upon existing antibody therapeutics for Clostridium difficile infections.

Epigenetic Prevention and Treatment of CDKL5 Deficiency Disorder

Researchers at the University of California, Davis have developed a targeted epigenetic approach for the prevention and treatment CDKL5 deficiency disorder.

Compositions and Methods for Treating Viral Infections

Researchers at the University of California, Davis (“UC Davis”) have developed methods for screening and targeting regions of viral genomes to identify drugs that inhibit the replication of RNA viruses.

Methods and Compositions for the Treatment of Huntington's Disease

There are no approved disease-modifying therapies for Huntington’s disease (HD), a fatal neurodegenerative condition caused by a heterozygous expansion of a CAG array in exon 1 of Huntingtin (Htt). Typically, HD patients are heterozygous for the toxic gain of function disease allele, yet expression of the wildtype version of the gene is essential. The inventors have developed methods and compositions to selectively silence expression from the disease-associated allele while leaving the wildtype version intact. The invention relies on the introduction of a 'poison' exon into the diseased allele wherein introduction of the poison exon may be accomplished by standard methods in the art, such as introduction of the exon sequences through homology-directed repair following targeted nuclease cleavage, transposon-associated targeted sequence introduction, base editing, and prime editing. Following the introduction of the poison exon, post-transcriptional splicing results in an RNA that is susceptible to nonsense mediated decay due to the introduction of a stop codon in the introduced exon. RNAs comprising the poison exon are subsequently degraded in the cell, effectively silencing expression of the mutant disease-associated allele.

Method For Generating Endotoxin-Free Gram-Negative Bacteria

The inventors have discovered that lipid A can be genetically eliminated from Caulobacter crescentus, dependent upon inactivation of the transcriptional regulator Fur and the presence of anionic sphingolipids called ceramide phosphoglycerate. The inventors identified and characterized genes responsible for ceramide phosphoglycerate synthesis. The inventors propose that other Gram-negative bacteria, including E. coli, can be engineered to eliminate lipid A by inactivating their Fur homologs, introducing genes for the synthesis of ceramide phosphoglycerate, or both. Bacteria thus engineered could be used for the endotoxin-free production of small molecule or protein-based pharmaceuticals, therapeutic bacteriophage, RNAs, or endotoxin-free therapeutic bacteria.BACKGROUND The bacterium Escherichia coli is used as a platform for the manufacture of 20-30% of the biopharmaceuticals currently marketed. E. coli, like other Gram-negative bacteria, possesses an outer membrane containing the glycolipid lipopolysaccharide (LPS). The innermost portion of LPS, lipid A, anchors LPS in the outer leaflet of the outer membrane. Lipid A, historically known as endotoxin, is a potent stimulator of the innate immune system in mammals. Even small amounts of endotoxin in the bloodstream can induce an unregulated, systemic inflammatory response known as sepsis. A major hurdle and cost in E. coli-based pharmaceutical production is the removal of endotoxin from each final product. Endotoxin removal strategies are developed on a case-by-case basis to find conditions in which the stable lipid A contaminant can be chemically separated from the desired product while not adversely affecting product recovery or activity. Industrial biotechnology could benefit from additional bacterial production platforms that eliminate the need for extensive processing to remove endotoxins. The challenge is that lipid A is almost always an essential structural component of the OM, meaning that it cannot be eliminated without causing the death of the bacterium. To date, only four species that normally contain lipid A have yielded mutant strains that completely lack lipid A and its biosynthetic precursors. However, these species are not well-developed platforms for industrial biotechnology. An E. coli strain (KPM22) has been developed that survives with only lipid IVA, an intermediate in the lipid A biosynthesis pathway. Lipid IVA contains fewer acyl chains than mature lipid A, causing a ~1000-fold reduction in its endotoxin activity. A modified version of this “endotoxin-free” strain is currently marketed by Lucigen under the trade name ClearColi (https://www.lucigen.com/faq-clearcoli.html).

Nuclear Delivery and Transcriptional Repression with a Cell-penetrant MeCP2

Methyl-CpG-binding-protein 2 (MeCP2) is a nuclear protein expressed in all cell types, especially neurons. Mutations in the MECP2 gene cause Rett syndrome (RTT), an incurable neurological disorder that disproportionately affects young girls. Strategies to restore MeCP2 expression phenotypically reverse RTT-like symptoms in male and female MeCP2-deficient mice, suggesting that direct nuclear delivery of functional MeCP2 could restore MeCP2 activity.The inventors have discovered that ZF-tMeCP2, a conjugate of MeCP2(aa13-71, 313-484) and the cell-permeant mini-protein ZF5.3, binds DNA in a methylation-dependent manner and reaches the nucleus of model cell lines intact at concentrations above 700 nM. When delivered to live cells, ZF-tMeCP2 engages the NCoR/SMRT co-repressor complex and selectively represses transcription from methylated promoters. Efficient nuclear delivery of ZF-tMeCP2 relies on a unique endosomal escape portal provided by HOPS-dependent endosomal fusion.In a comparative evaluation, the inventors observed the Tat conjugate of MeCP2 (Tat-tMeCP2) (1) degrades within the nucleus, (2) is not selective for methylated promoters, and (3) traffics in a HOPS-independent manner. These results support the feasibility of a HOPS-dependent portal for delivering functional macromolecules to the cell interior using the cell-penetrant mini-protein ZF5.3. Such a strategy could broaden the impact of multiple families of protein-derived therapeutics.

Type III CRISPR-Cas System for Robust RNA Knockdown and Imaging in Eukaryotes

Type III CRISPR-Cas systems recognize and degrade RNA molecules using an RNA-guided mechanism that occurs widely in microbes for adaptive immunity against viruses. The inventors have demonstrated that this multi-protein system can be leveraged for programmable RNA knockdown of both nuclear and cytoplasmic transcripts in mammalian cells. Using single-vector delivery of the S. thermophilus Csm complex, RNA knockdown was achieved with high efficiency (90-99%) and minimal off-targets, outperforming existing technologies of shRNA- and Cas13-mediated knockdown. Furthermore, unlike Cas13, Csm is devoid of trans-cleavage activity and thus does not induce non-specific transcriptome-wide degradation and cytotoxicity. Catalytically inactivated Csm can also be used for programmable RNA-binding, which the inventors exploit for live-cell RNA imaging. This work demonstrates the feasibility and efficacy of multi-subunit CRISPR-Cas effector complexes as RNA-targeting tools in eukaryotes.

Methods Related To Cell-Microgel Encapsulation In Injectable Formulations

Injectable hydrogels are attracting increasing interest for the therapeutic delivery of cells to tissue. However, these hydrogel formulations can suffer from engraftment efficiencies of less than 5% when delivered to native tissue. These poor engraftment efficiency rates are often attributed to high shear stresses during delivery and inability to provide a stable three-dimensional niche at the delivery site. The inventors have developed a technique for encapsulating cells in the pore space between microscopic hydrogel particles by employing the yield stress fluid properties of packs of microgels. The technology protects the cells from mechanical stress during delivery and facilitates integration to the native tissue. During delivery, the packs of microgels undergo plug flow in which the pressure drop across the length of the pipe is compensated solely by frictional forces at the interface between the pipe wall and microgels. At the delivery site, the pack of microgels behave as an elastic solid across the range of physiological frequencies and provide a stable 3D culture paradigm to support engraftment.Furthermore, the inventors address the challenges associated with cryopreserving, transporting, and delivering this injectable formulation from benchtop-to-bedside with a concept for a perfusable delivery device. The device encapsulates cells in the pore space of the microgels and confines the formulation to a fixed volume where researchers can perfuse liquid freeze/thaw or maintenance media, differentiation factors, and anti-inflammatory agents at virtually any time prior to delivery to the tissue. The porous microgel network facilitates this process and makes the formulation amenable to transport and storage which would otherwise be unattainable in hydrogel formulations.

Membrane-Associated Accessory Protein Variants Confer Increased AAV Production

The inventors have developed an engineering approach to identify novel and nonobvious membrane-associated accessory protein (MAAP) sequence variants that confer increased Adeno-associated virus (AAV) secretion during packaging. The technique is based upon the iterative process of sequence diversification and selection of functional gene variants known as directed evolution. First, the inventors generated a library of more than 1E6 MAAP variants. The variants were subjected to five rounds of packaging into an AAV2 capsid for which MAAP expression was inactivated without altering the viral protein VP1 open reading frame (ORF) (AAV2-MAAP-null). Among each iterative packaging round, the inventors observed a progressive increase in both the overall titer and ratio of secreted vector genomes conferred by the bulk selected MAAP library population. Next-generation sequencing uncovered common mutational features that were enriched up to over 10,000-fold on the amino acid level. Individual MAAP variants were isolated and systematically tested for effect on recombinant AAV2-MAAP-null packaging in HEK293 cells. The inventors predict that this work may be applicable to increasing per-cell AAV output in industrial settings, potentially reducing global costs and increasing functional vector recovery in downstream manufacturing processes.BACKGROUNDParvoviruses are small, single-stranded DNA viruses that are ubiquitously found in many animal species. AAV is a prototypic dependoparvovirus whose replication cycle requires the function of helper genes from larger co-infected viruses such as Adenoviruses or Herpesviruses. The natural genome of AAV contains ~4.7 kb of ssDNA that encodes up to ten known proteins in a highly overlapped fashion. The rep gene encodes four protein products named based on their molecular weight: Rep72 and Rep68 facilitate genomic replication, whereas Rep52, and Rep40 play essential roles in loading nascent ssDNA genomes into assembled capsids. Downstream of rep lies the cap gene, which encodes three known protein products off of overlapping reading frames: VP1, VP2, and VP3 are structural proteins that assemble to form the capsid, the assembly activating protein (AAP) targets VP proteins to the nucleus and is involved in capsid assembly. The most recently discovered AAV-encoded gene is the membrane-associated accessory protein (MAAP). MAAP is encoded by an alternative ORF in the AAV cap gene that is found in all presently reported natural serotypes. Gene delivery by recombinant AAV (rAAV) have shown significant success in both research and clinical gene therapy applications. In the rAAV system, Rep and Cap are removed from between AAV’s 5’ and 3’ inverted terminal repeats (ITRs) and provided in trans. Instead, a transgene of interest is inserted between the ITRs and subsequently packaged into the nascent AAV capsids. However, manufacturing quantities of good manufacturing practice (GMP)-grade rAAVs necessary to achieve current and projected dosing requirements–particularly in a clinical context–presents a significant hurdle to expanding rAAV-based gene therapies. Recently, evidence has emerged supporting a functional role of MAAP in AAV egress. This led to the hypothesis that MAAP could be engineered to facilitate increased levels of secreted AAV produced from HEK293 cells. 

Synthetic Minimal Hammerhead Nuclease Ribozymes With Greatly Enhanced And Efficient Specific Cleavage Activity

The hammerhead RNA sequence within satellite RNA genomes occurs at theinterface of two monomeric segments of a linear concatamer following rolling circle replication. Although it is, in that context, a single self-cleaving strand of RNA that is capable of catalyzing only a single, albeit highly specific, cleavage reaction, the hammerhead RNA can be artificially engineered to create a true multiple-turnover ribozyme simply by separating the molecule into discrete catalytic and target strands. The latter constructs have been studied in vitro and also correspond to hammerhead ribozyme sequences that have used in targeting other RNAs

Methods To Rapidly Measure Antibodies And Other Biomolecules In Clinical Specimens Utilizing Biolayer Interferometry

The rapid spread of SARS-CoV-2 and associated declaration of a global pandemic in 2020 underscore the importance of rapid and accurate infectious disease testing. Serological tests,  which facilitate vaccine development and identification of population spread, are commonly used as countermeasures to infection. Existing serological testing methods, like lateral flow immunoassays, are not quantitative and reliably sensitive though. Other immunoassays have better sensitivity and specificity but require long incubation times and are labor-intensive.  

RNA-Guided Fusion Proteins for Targeted Diversification of Cytoplasmic DNA

The inventors have developed a method of mutagenizing user-defined regions of cytoplasmic DNA using a single guide RNA (sgRNA) or combinations of sgRNAs and a highly engineered fusion polypeptide comprising: a nuclear export sequence (NES)-containing, engineered nuclear localization sequence (NLS)-lacking, enzymatically active, RNA-guided endonuclease that introduces a single-stranded break in cytoplasmic DNA, and an error-prone DNA polymerase. This novel technology encompasses and provides evidence for the use of RNA-guided nucleases with relaxed PAM requirements, which are particularly useful for AT-rich targets such as the vaccinia virus genome. The inventors show that the truncation of up to several base pairs from the PAM-distal template binding region of the sgRNAs significantly increases the functional activity and specificity of the targeted mutagenesis complex. Moreover, the invention describes specific methods for the use of this technology to edit cytoplasmically replicating viruses with large DNA genomes, using poxviruses as a model system. The novel editing platform and methods selectively and continuously accelerate diversification of user-defined sites in the vaccinia genome during infection, while retaining most library members, due to significantly lowering deleterious off-target mutations. BACKGROUND Nucleocytoplasmic large DNA viruses (NCLDVs) are a group of viruses that harbor large (150 kbp - 1.2 mbp) double-stranded DNA genomes and replicate in the cytoplasm of eukaryotic cells. An example of an NCLDV that has historically been among the most prominent tools in human health is vaccinia, a poxvirus. Hundreds of millions of humans have been intentionally inoculated with vaccinia as part of a global effort to eliminate smallpox, which was declared eradicated in 1980.Vaccinia and some other poxviruses remain highly scientifically relevant in the post-eradication world. They are useful as vaccines against deadly poxvirus outbreaks that could potentially arise from natural spillover, bioterrorism, or biowarfare, as well as due to their therapeutic promise as oncolytic agents to selectively deliver anti-cancer transgenes and recruit adaptive immunity while leaving healthy cells unharmed. Directed evolution is a powerful engineering technique for evolving new phenotypes that are beneficial for biotechnological applications but for which there may have never been a selective pressure to evolve in nature. Both natural and directed evolution depend upon generation of genetic diversity, followed by a selective pressure. While natural evolution generates genetic diversity randomly and throughout the entirety of the genome, directed evolution ideally focuses mutations within specific genomic windows connected to the phenotype that one wishes to engineer. However, there is a need in the art for compositions and methods for mutagenizing a target DNA in the cytoplasm of mammalian cells. NCLDVs, which either partially or entirely express their own replicative and translational machinery independent of the nucleus, are difficult, and in many cases impossible, to produce from plasmid DNA in cells. Thus, NCLDVs are not amenable to standard in vitro molecular diversification strategies.  

Genetically Engineered Dendritic Cell-Derived Vaccines

Researchers at the University of California, Irvine have developed a new vaccine which generates a targeted, specific immune response with fewer complications than currently available vaccines.

Methods To Generate Novel Acyl-Trna Species

The inventors have discovered PylRS enzymes that accept -thio acids, N-formyl-L-amino acids, and diverse -carboxyl acid monomers (malonic acids) that are formally precursors to polyketide natural products. These monomers are all accommodated and accepted by the translation apparatus in vitro. High-resolution structural analysis of the complex between one such PylRS enzyme and a meta-substituted 2-benzylmalonate derivative reveals an active site that discriminates pro-chiral carboxylates and accommodates the large size and distinct electrostatics of an -carboxyl acid substituent.This discovery emphasizes the potential of PylRS for evolving new enzymes capable of encoding diverse non-L-amino acids in synergy with natural or evolved ribosomes. The absence of orthogonal aminoacyl-tRNA synthetase enzymes that accept non-L-amino acids is the primary bottleneck hindering the in vivo translation of sequence-defined hetero-oligomers. 

Integrin Binding to P-Selectin as a Treatment for Cancer and Inflammation

Researchers at the University of California, Davis have developed a potential drug target for cancer and inflammation by studying the binding of integrins to P-selectin.

Modulating MD-2-Integrin Interaction for Sepsis Treatment

Researchers at the University of California, Davis have developed a potential therapeutic treatment for sepsis by modulating the interaction between integrins and Myeloid Differentiation factor 2 (MD-2).

Tumor-Suppressing Growth Factor Decoy

Researchers at the University of California, Davis have developed dominant-negative FGF2 antagonists that suppress angiogenesis and tumor growth.

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