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Knight, K.

Publications and source records attributed to Knight, K..

4 recordsLinked to original sources

Preclinical Development of a Vectorized Artificial miRNA Gene Therapy for Tauopathies

Tauopathies, including Alzheimers disease, are neurodegenerative disorders characterized by the accumulation of microtubule-associated protein tau, which is closely linked to cognitive decline. Reduction of tau is a potential and promising strategy for addressing tau-linked brain disorders. We report the development of a therapeutic approach using adeno-associated virus mediated delivery of an artificial microRNA targeting human tau. In a tauopathy mouse model, we demonstrate that a one-time intra-cisterna magna administration of vector resulted in reduced total tau, decreased pathological tau seeds, fewer tau inclusions, and amelioration of tau-related neuropathology. Notably, intervention at late disease stages, after onset of tau deposition and neurodegeneration, improved quality of life and extended survival. We further demonstrated the durability of therapeutic benefit and defined the minimally effective dose in tauopathy mice. These findings provide preclinical support for the advancement of a vectorized tau-lowering strategy as a disease-modifying approach for tauopathies and enable progression towards an investigational new drug application.

neuroscience↗

AAV-mediated gene therapy for SLC13A5 citrate transporter disorder rescues epileptic and metabolic phenotypes

SLC13A5 citrate transporter disorder is a rare epileptic encephalopathy caused by loss of function pathogenic variants in the SLC13A5 gene. Loss of sodium/citrate cotransporter (NaCT) function causes a severe early life epilepsy resulting in life-long developmental disabilities and increased extracellular citrate. Current antiseizure medications may reduce seizure frequency, yet more targeted treatments are needed to address the epileptic and neurodevelopmental SLC13A5 phenotype. We performed preclinical studies in SLC13A5 deficient mice evaluating phenotype rescue with adeno-associated virus (AAV) vector carrying a functional copy of the human SLC13A5 gene (AAV9/SLC13A5). Cerebrospinal fluid-delivery of AAV9/SLC13A5 decreased extracellular citrate levels, normalized electrophysiologic and sleep architecture abnormalities, and restored resistance to chemically induced seizures and death. Treatment benefits were achieved with administration during early brain development and in young adult mice, supporting a broad therapeutic window for this disorder. Comparison of delivery routes in young adult KO mice showed that higher brain targeting achieved with intra-cisterna magna delivery resulted in greater treatment benefit as compared to intrathecal lumbar puncture delivery. Together, these results support further development of AAV9/SLC13A5 for treating SLC13A5 citrate transporter disorder. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=90 SRC="FIGDIR/small/663044v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@ddc591org.highwire.dtl.DTLVardef@1d5e967org.highwire.dtl.DTLVardef@ce6c2forg.highwire.dtl.DTLVardef@209176_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

Monoclonal Nanobodies Alter the Activity and Assembly of the Yeast Vacuolar H+-ATPase

The vacuolar ATPase (V-ATPase; V1Vo) is a multi-subunit rotary nanomotor proton pump that acidifies organelles in virtually all eukaryotic cells, and extracellular spaces in some specialized tissues of higher organisms. Evidence suggests that metastatic breast cancers mislocalize V-ATPase to the plasma membrane to promote cell survival and facilitate metastasis, making the V-ATPase a potential drug target. We have generated a library of camelid single-domain antibodies (Nanobodies; Nbs) against lipid-nanodisc reconstituted yeast V-ATPase Vo proton channel subcomplex. Here, we present an in-depth characterization of three anti-Vo Nbs using biochemical and biophysical in vitro experiments. We find that the Nbs bind Vo with high affinity, with one Nb inhibiting holoenzyme activity and another one preventing enzyme assembly. Using cryoEM, we find that two of the Nbs bind the c subunit ring of the Vo on the lumen side of the complex. Additionally, we show that one of the Nbs raised against yeast Vo can pull down human V-ATPase (HsV1Vo). Our research demonstrates Nb versatility to target and modulate the activity of the V-ATPase, and highlights the potential for future therapeutic Nb development.

biochemistry↗

Extracellular Matrix Dysfunction in Sorsby Patient-Derived Retinal Pigment Epithelium

Sorsby Fundus Dystrophy (SFD) is a rare form of macular degeneration that is clinically similar to age-related macular degeneration (AMD), and a histologic hallmark of SFD is a thick layer of extracellular deposits beneath the retinal pigment epithelium (RPE). Previous studies of SFD patient-induced pluripotent stem cell (iPSC) derived RPE differ as to whether these cultures recapitulate this key clinical feature by forming increased drusenoid deposits. The primary purpose of this study is to examine whether SFD patient-derived iPSC-RPE form basal deposits similar to what is found in affected family member SFD globes and to determine whether SFD iPSC RPE may be more oxidatively stressed. We performed a careful comparison of iPSC RPE from three control individuals, multiple iPSC clones from two SFD patients iPSC RPE, and post-mortem eyes of affected SFD family members. We also examined the effect of CRISPR-Cas9 gene correction of the S204C TIMP3 mutation on RPE phenotype. Finally, targeted metabolomics analysis with liquid chromatography and mass spectrometry analysis and stable isotope-labeled metabolite analysis was performed to determine whether SFD RPE are more oxidatively stressed. We found that SFD iPSC-RPE formed significantly more sub-RPE deposits ([~]6-90 m in height) compared to control RPE at 8 weeks. These deposits were similar in composition to the basal laminar drusen found in SFD family member globes by immunofluorescence staining and TEM imaging. S204C TIMP3 correction by CRISPR-Cas9 gene editing in SFD iPSC RPE cells resulted in significantly reduced basal laminar and sub-RPE calcium deposits. We detected a [~]18-fold increase in TIMP3 accumulation in the extracellular matrix (ECM) of SFD RPE, and targeted metabolomics showed that intracellular 4-hydroxyproline, a major breakdown product of collagen, is significantly elevated in SFD RPE, suggesting increased ECM turnover. Finally, SFD RPE cells have decreased intracellular reduced glutathione and were found to be more vulnerable to oxidative stress. Our findings suggest that elements of SFD pathology can be demonstrated in culture which may lead to insights into disease mechanisms.

cell biology↗