Saliva and Saliva Extracellular Vesicles for Biomarker Candidate Identification-Assay Development and Pilot Study in Amyotrophic Lateral Sclerosis.

Saliva is gaining increasing attention as a source of biomarkers due to non-invasive and undemanding collection access. Extracellular vesicles (EVs) are nano-sized, cell-released particles that contain molecular information about their parent cells. In this study, we developed methods for saliva biomarker candidate identification using EV-isolation and proteomic evaluation. We used pooled saliva samples for assay development. EVs were isolated using membrane affinity-based methods followed by their characterization using nanoparticle tracking analysis and transmission electron microscopy. Subsequently, both saliva and saliva-EVs were successfully analyzed using proximity extension assay and label-free quantitative proteomics. Saliva-EVs had a higher purity than plasma-EVs, based on the expression of EV-proteins and albumin. The developed methods could be used for the analysis of individual saliva samples from amyotrophic lateral sclerosis (ALS) patients and controls (n = 10 each). The starting volume ranged from 2.1 to 4.9 mL and the amount of total isolated EV-proteins ranged from 5.1 to 42.6 µg. Although no proteins were significantly differentially expressed between the two groups, there was a trend for a downregulation of ZNF428 in ALS-saliva-EVs and an upregulation of IGLL1 in ALS saliva. In conclusion, we have developed a robust workflow for saliva and saliva-EV analysis and demonstrated its technical feasibility for biomarker discovery.

Identification of α-Synuclein Proaggregator: Rapid Synthesis and Streamlining RT-QuIC Assays in Parkinson's Disease.

We report the discovery of two compounds, TKD150 and TKD152, that promote the aggregation of α-synuclein (aSN) using a real-time quaking-induced conversion (RT-QuIC) assay to detect abnormal aSN. By utilizing a Pd-catalyzed C-H arylation of benzoxazole with iodoarenes and implementing a planar conformation to the design, we successfully identified TKD150 and TKD152 as proaggregators for aSN. In comparison to a previously reported proaggregator, PA86, the two identified compounds were able to promote aggregation of aSN at twice the rate. Application of TKD150 and TKD152 to the RT-QuIC assay will shorten the inherent lag time and may allow wider use of this assay in clinical settings for the diagnosis of α-synucleinopathy-related diseases.

Highly-sensitive simultaneous quantitation of glucosylsphingosine and galactosylsphingosine in human cerebrospinal fluid by liquid chromatography/tandem mass spectrometry.

Mutations in the GBA gene, encoding glucocerebrosidase (GCase), are linked to Gaucher disease (GD) and are the most common risk factors for Parkinson's disease (PD). The glucosylsphingosine (GlcSph) in cerebrospinal fluid (CSF) is used as a pharmacodynamic marker for GCase functionalizing therapy in GD patients. Its isobaric structural isomer, galactosylsphingosine (GalSph, psychosine), is also used as a diagnostic blood marker in Krabbe disease (KD) which is caused by a deficiency in ß-galactocerebrosidase (GALC). However, there are no reports of GlcSph quantification in the CSF of GBA-PD patients and normal healthy humans due to low concentrations. In this study, we successfully quantified GlcSph in healthy human CSF using a highly sensitive LC-MS/MS method with separation of GalSph. The lower limit of quantitation (LLOQ) was 0.1 pg/mL. Additionally, GlcSph and GalSph concentrations in the plasma and brain were determined using different LC-MS/MS methods. The mean concentrations of GlcSph and GalSph in normal human CSF were 1.07 and 9.44 pg/mL, respectively. The GalSph level in the CSF and brain was higher than that of GlcSph, whereas plasma GalSph was lower than GlcSph. Because GCase and GALC are expressed in the brain and the peripheral tissues, GlcSph and GalSph in CSF would be a good surrogate of concentration change in the brain by targeted therapies. This method measures normal levels of GlcSph and GalSph in healthy human CSF without accumulation of sphingolipids, and confirms whether abnormal CSF concentrations can be reduced to normal levels by therapy.

A pilot study using proximity extension assay of cerebrospinal fluid and its extracellular vesicles identifies novel amyotrophic lateral sclerosis biomarker candidates.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder which is characterized by progressive degeneration of the motor system. Typically, the disease starts with focal weakness which spreads to involve most muscles and leads to death from respiratory failure within five years of diagnosis. Due to the heterogenic nature of the disease, diagnostics is complex, and it generally takes twelve months from symptom-onset to diagnosis. The discovery of novel biomarkers could lead to accelerated diagnosis, earlier start of treatment, improved patient-segmentation, and treatment follow-up as well as an increased insight into the pathology. Here, we analyzed cerebrospinal fluid (CSF) and CSF-derived extracellular vesicles (CSF-EVs) from ALS-patients and matched controls (n = 9 each) using the ultra-sensitive proximity extension assay (PEA), cardiovascular III-panel. On average, 84 and 61 proteins could be detected in CSF and CSF-EVs respectively. In CSF, three proteins were significantly upregulated in ALS-patients (Junctional Adhesion Molecule A Protein, Tumor necrosis factor receptor 2 and Chitinase 1) while myoglobin was down-regulated. In CSF-EVs, no significantly differentially expressed proteins were identified, but there was a trend for downregulation of Perlecan. To our knowledge, only CHIT1 has been previously described as a CSF-based biomarker candidate for ALS. By combining the four differentially expressed markers in CSF and support vector machine algorithm, all ALS patients and 8 of 9 controls were correctly classified. In conclusion, we here demonstrate the feasibility of using PEA of CSF and CSF-EVs for biomarker discovery and propose three de novo biomarker candidates for ALS, however, further studies are necessary to demonstrate clinical usability.

Quantitative comparison of the mRNA content of human iPSC-derived motor neurons and their extracellular vesicles.

Extracellular vesicles (EVs) contain various cargo molecules, including RNAs and proteins. EVs, which include exosomes, are predicted to be suitable surrogates of their source cells for liquid biopsy to measure biomarkers. Several studies have performed qualitative comparisons of cargo molecule repertoires between source cells and their EVs. However, quantitative comparisons have not been reported so far. Furthermore, many studies analyzed microRNAs or proteins in EVs, but not mRNAs. In this study, we analyzed mRNAs in motor neurons and their EVs. Normal human-induced pluripotent stem cells were differentiated into motor neurons, and comprehensive analysis of mRNAs in the cells and their EVs was performed by RNA sequencing. Differential analysis between cellular and EV mRNAs was performed by edgeR after normalization of read count. The results suggest that signatures in the abundance of EV mRNAs were different from those of cellular mRNAs. Comparison of intracellular vesicle and EV mRNA abundance showed negatively and positively biased genes in the EVs. Gene Ontology analysis revealed that the genes showing negatively biased abundance in the EVs were enriched in many functions regarding neuronal development. In contrast, the positively biased genes were enriched in functions regarding cellular metabolism and protein synthesis. These results suggest that mRNAs in motor neurons are loaded into EVs to regulate certain mechanisms, which are yet to be elucidated.

Analysis of Cerebrospinal Fluid Extracellular Vesicles by Proximity Extension Assay: A Comparative Study of Four Isolation Kits.

There is a lack of reliable biomarkers for disorders of the central nervous system (CNS), and diagnostics still heavily rely on symptoms that are both subjective and difficult to quantify. The cerebrospinal fluid (CSF) is a promising source of biomarkers due to its close connection to the CNS. Extracellular vesicles are actively secreted by cells, and proteomic analysis of CSF extracellular vesicles (EVs) and their molecular composition likely reflects changes in the CNS to a higher extent compared with total CSF, especially in the case of neuroinflammation, which could increase blood-brain barrier permeability and cause an influx of plasma proteins into the CSF. We used proximity extension assay for proteomic analysis due to its high sensitivity. We believe that this methodology could be useful for de novo biomarker discovery for several CNS diseases. We compared four commercially available kits for EV isolation: MagCapture and ExoIntact (based on magnetic beads), EVSecond L70 (size-exclusion chromatography), and exoEasy (membrane affinity). The isolated EVs were characterized by nanoparticle tracking analysis, ELISA (CD63, CD81 and albumin), and proximity extension assay (PEA) using two different panels, each consisting of 92 markers. The exoEasy samples did not pass the built-in quality controls and were excluded from downstream analysis. The number of detectable proteins in the ExoIntact samples was considerably higher (~150% for the cardiovascular III panel and ~320% for the cell regulation panel) compared with other groups. ExoIntact also showed the highest intersample correlation with an average Pearson's correlation coefficient of 0.991 compared with 0.985 and 0.927 for MagCapture and EVSecond, respectively. The median coefficient of variation was 5%, 8%, and 22% for ExoIntact, MagCapture, and EVSecond, respectively. Comparing total CSF and ExoIntact samples revealed 70 differentially expressed proteins in the cardiovascular III panel and 17 in the cell regulation panel. To our knowledge, this is the first time that CSF EVs were analyzed by PEA. In conclusion, analysis of CSF EVs by PEA is feasible, and different isolation kits give distinct results, with ExoIntact showing the highest number of identified proteins with the lowest variability.

Identification of biomarkers for amyotrophic lateral sclerosis by comprehensive analysis of exosomal mRNAs in human cerebrospinal fluid.

BACKGROUND: Exosomes are a subset of extracellular vesicles 30-200 nm in diameter secreted from cells, which contain functional mRNAs and microRNAs. Cerebrospinal fluid (CSF) is the primary source for liquid biopsy to examine diseases in central nervous system. To date, there is no available method to analyze exosomal mRNAs comprehensively in human CSF. METHODS: The main purpose of this study is to established the methodology of comprehensive analysis of exosomal mRNAs in CSF by a highly sensitive next-generation sequencing. The signatures of CSF exosomal mRNAs were then compared between four normal healthy donors and four sporadic amyotrophic lateral sclerosis patients to identify disease-related biomarkers. Differentially expressed genes were identified by DESeq2. RESULTS: RNA sequencing from CSF exosomes was successfully performed, that was demonstrated by the high pearson's product-moment correlation coefficient (r = 0.993) in the technical replicates. Also, position coverage analysis revealed that most detected mRNAs retained their integrity throughout their full-length in CSF exosomes. In CSF exosomes from normal healthy donors, an average of 14,807 genes were detected, of which 4580 genes were commonly detected among four individuals, including neuron-enriched genes such as TUBB3 and CAMK2A. In comparison with exosomal mRNAs in CSF from four patients with amyotrophic lateral sclerosis, 543 genes were significantly changed, as represented by CUEDC2. Gene Ontology analysis and pathway analysis with these genes revealed functional enrichment of ubiquitin-proteasome pathway, oxidative stress response, and unfolded protein response. These pathways are related to pathomechanisms of amyotrophic lateral sclerosis. CONCLUSION: We successfully established the methodology of comprehensive analysis of exosomal mRNAs in human CSF. It was shown to be useful to identify disease biomarkers for central nervous system. Several genes, such as CUEDC2, in CSF exosomes were suggested to be candidate disease biomarkers for amyotrophic lateral sclerosis.

Anti-tumor activity of KNTC2 siRNA in orthotopic tumor model mice of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is still one of the major causes of cancer-related death. Kinetochore-associated protein 2 (KNTC2) is specifically upregulated in tumor tissues of HCC patients and recognized as a potential candidate target for the treatment of HCC. However, the relationship between KNTC2 and in vivo tumor growth of HCC is not yet fully understood. Here we encapsulated KNTC2 siRNAs into a lipid nanoparticle (LNP) and investigated their knockdown activity, target engagement marker, anti-tumor activity and hepatotoxicity in an orthotopic HCC model mice of Hep3B-luc cells. Single i.v. administration of KNTC2 siRNA-LNP specifically suppressed the expression levels of both human KNTC2 mRNA and mouse Kntc2 mRNA in tumor tissues. Phosphorylation levels of histone H3 (HH3) at serine 10 in tumor tissues were increased by KNTC2 siRNA-LNP. Repeated administration of KNTC2 siRNA-LNP (twice a week) specifically inhibited the growth of tumor tissues without increasing the plasma AST and ALT levels. Their growth inhibitory activities were consistent with knockdown activities. These data strongly indicated that KNTC2 is a promising target for the treatment of HCC and that phosphorylated HH3 at serine 10 is one of the target engagement markers for KNTC2.

Discovery of peptidic miR-21 processing inhibitor by mirror image phage display: A novel method to generate RNA binding D-peptides.

A novel method to generate RNA binding D-peptide has been developed. To achieve the screening method, phage display was applied to "Mirrored" RNA (L-enantiomer of RNA). We have selected pre-miR21 as an initial screening target to demonstrate the method. The mirrored pre-miR-21 binding peptide sequences were successfully obtained, and were chemically synthesized using D-amino acids. D-peptide is expected to have favorable properties as a drug candidate such as protease resistance and low immunogenicity. As a result of binding evaluation of the D-peptide to pre-miR-21, the EC50 value was 440nM. In addition, the D-peptide possessed inhibition activity to miR-21 processing.

Development of antibody-siRNA conjugate targeted to cardiac and skeletal muscles.

Despite considerable efforts to develop efficient carriers, the major target organ of short-interfering RNAs (siRNAs) remains limited to the liver. Expanding the application outside the liver is required to increase the value of siRNAs. Here we report on a novel platform targeted to muscular organs by conjugation of siRNAs with anti-CD71 Fab' fragment. This conjugate showed durable gene-silencing in the heart and skeletal muscle for one month after intravenous administration in normal mice. In particular, 1µg siRNA conjugate showed significant gene-silencing in the gastrocnemius when injected intramuscularly. In a mouse model of peripheral artery disease, the treatment with myostatin-targeting siRNA conjugate by intramuscular injection resulted in significant silencing of myostatin and hypertrophy of the gastrocnemius, which was translated into the recovery of running performance. These data demonstrate the utility of antibody conjugation for siRNA delivery and the therapeutic potential for muscular diseases.

Characterization of a variety of neutralizing anti-heparin-binding epidermal growth factor-like growth factor monoclonal antibodies by different immunization methods.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a member of the epidermal growth factor family. The accumulated evidence on the tumor-progressing roles of HB-EGF has suggested that HB-EGF-targeted cancer therapy is expected to be promising. However, the generation of neutralizing anti-HB-EGF monoclonal antibodies (mAbs) has proved difficult. To overcome this difficulty, we performed a hybridoma approach using mice from different genetic backgrounds, as well as different types of HB-EGF immunogens. To increase the number of hybridoma clones to screen, we used an electrofusion system to generate hybridomas and a fluorometric microvolume assay technology to screen anti-HB-EGF mAbs. We succeeded in obtaining neutralizing anti-HB-EGF mAbs, primarily from BALB/c and CD1 mice, and these were classified into 7 epitope bins based on their competitive binding to the soluble form of HB-EGF (sHB-EGF). The mAbs showed several epitope bin-dependent characteristics, including neutralizing and binding activity to human sHB-EGF, cross-reactivity to mouse/rat sHB-EGF and binding activity to the precursor form of HB-EGF. The neutralizing activity was also validated in colony formation assays. Interestingly, we found that the populations of mAb bins and the production rates of the neutralizing mAbs were strikingly different by mouse strain and by immunogen type. We succeeded in generating a variety of neutralizing anti-HB-EGF mAbs, including potent sHB-EGF neutralizers that may have potential as therapeutic agents for treating HB-EGF-dependent cancers. Our results also suggest that immunization approaches using different mouse strains and immunogen types affect the biological activity of individual neutralizing antibodies.

Development of novel humanized anti-CD20 antibodies based on affinity constant and epitope.

We describe novel humanized anti-CD20 monoclonal antibodies (mAbs) developed for therapeutic use on the basis of their physicochemical properties and cellular cytotoxicity. A distinct correlation between apparent dissociation constants (K(d)) and apoptotic activity for eight murine anti-CD20 mAbs (OUBM1-OUBM8) and previously-developed murine anti-CD20 mAbs enabled us to categorize anti-CD20 mAbs into two groups. Group A mAbs had lower K(d) values and did not induce definite apoptosis, while Group B mAbs had greater K(d) values and did induce definite apoptosis. A murine version mAb of rituximab, 2B8, belongs to Group B. An epitope analysis showed that the epitope of two murine mAbs, OUBM3 and OUBM6, differed from that of 2B8 or 2F2 (ofatumumab). Two mAbs, OUBM3 from Group A and OUBM6 from Group B, were selected and humanized. As expected, the humanized OUBM3 with the lower K(d) did not induce apoptosis, while the humanized OUBM6 (hOUBM6) with the greater K(d) did. Both hOUBM3 and hOUBM6 induced highly-effective, complement-dependent cytotoxicity and antibody-dependent, cell-mediated cytotoxicity against Burkitt's and follicular lymphomas. Importantly, hOUBM6 exhibited cellular cytotoxicity against diffuse, large B cells that are less effectively depleted by rituximab and also exhibited effective cytotoxicity against tumor cells from human CD20(+) leukemia and lymphoma patients. These results suggest the potential impact of the further development of our anti-CD20 mAbs. Our study shows that the selection of mAbs based on their physicochemical parameters, followed by the biological activity assessment for the selected mAbs, is a rational and efficient approach for pharmaceutical mAb development.