Automated whole slide morphometry of sural nerve biopsy using machine learning.

AIM: The morphometry of sural nerve biopsies, such as fibre diameter and myelin thickness, helps us understand the underlying mechanism of peripheral neuropathies. However, in current clinical practice, only a portion of the specimen is measured manually because of its labour-intensive nature. In this study, we aimed to develop a machine learning-based application that inputs a whole slide image (WSI) of the biopsied sural nerve and automatically performs morphometric analyses. METHODS: Our application consists of three supervised learning models: (1) nerve fascicle instance segmentation, (2) myelinated fibre detection and (3) myelin sheath segmentation. We fine-tuned these models using 86 toluidine blue-stained slides from various neuropathies and developed an open-source Python library. RESULTS: Performance evaluation showed (1) a mask average precision (AP) of 0.861 for fascicle segmentation, (2) box AP of 0.711 for fibre detection and (3) a mean intersection over union (mIoU) of 0.817 for myelin segmentation. Our software identified 323,298 nerve fibres and 782 fascicles in 70 WSIs. Small and large fibre populations were objectively determined based on clustering analysis. The demyelination group had large fibres with thinner myelin sheaths and higher g-ratios than the vasculitis group. The slope of the regression line from the scatter plots of the diameters and g-ratios was higher in the demyelination group than in the vasculitis group. CONCLUSION: We developed an application that performs whole slide morphometry of human biopsy samples. Our open-source software can be used by clinicians and pathologists without specific machine learning skills, which we expect will facilitate data-driven analysis of sural nerve biopsies for a more detailed understanding of these diseases.

Highly efficient silencing of microRNA by heteroduplex oligonucleotides.

AntimiR is an antisense oligonucleotide that has been developed to silence microRNA (miRNA) for the treatment of intractable diseases. Enhancement of its in vivo efficacy and improvement of its toxicity are highly desirable but remain challenging. We here design heteroduplex oligonucleotide (HDO)-antimiR as a new technology comprising an antimiR and its complementary RNA. HDO-antimiR binds targeted miRNA in vivo more efficiently by 12-fold than the parent single-stranded antimiR. HDO-antimiR also produced enhanced phenotypic effects in mice with upregulated expression of miRNA-targeting messenger RNAs. In addition, we demonstrated that the enhanced potency of HDO-antimiR was not explained by its bio-stability or delivery to the targeted cell, but reflected an improved intracellular potency. Our findings provide new insights into biology of miRNA silencing by double-stranded oligonucleotides and support the in vivo potential of this technology based on a new class of for the treatment of miRNA-related diseases.

Intrathecal AAV serotype 9-mediated delivery of shRNA against TRPV1 attenuates thermal hyperalgesia in a mouse model of peripheral nerve injury.

Gene therapy for neuropathic pain requires efficient gene delivery to both central and peripheral nervous systems. We previously showed that an adenoassociated virus serotype 9 (AAV9) vector expressing short-hairpin RNA (shRNA) could suppress target molecule expression in the dorsal root ganglia (DRG) and spinal cord upon intrathecal injection. To evaluate the therapeutic potential of this approach, we constructed an AAV9 vector encoding shRNA against vanilloid receptor 1 (TRPV1), which is an important target gene for acute pain, but its role in chronic neuropathic pain remains unclear. We intrathecally injected it into the subarachnoid space at the upper lumbar spine of mice 3 weeks after spared nerve injury (SNI). Delivered shTRPV1 effectively suppressed mRNA and protein expression of TRPV1 in the DRG and spinal cord, and it attenuated nerve injury-induced thermal allodynia 10-28 days after treatment. Our study provides important evidence for the contribution of TRPV1 to thermal hypersensitivity in neuropathic pain and thus establishes intrathecal AAV9-mediated gene delivery as an investigative and potentially therapeutic platform for the nervous system.

[Recent progress and prospect in oligonucleotide therapeutics].

Remarkable progress has been made in chemical modification and nonviral delivery systems that improve the properties and efficacy of therapeutics oligonucleotides therapeutics, such as antisense oligonucleotide (ASO) and small interfering RNA(siRNA). ASOs act through various mechanisms including the degradation of mRNA by RNase H (gapmer-type ASO) and the modulation alternative splicing patterns(splice switching oligonucleotide). Recent favorable outcomes in clinical trials for cancers and genetic diseases such as familial amyloid polyneuropathy and Duchenne muscular dystrophy indicate high clinical potency of oligonucleotide therapeutics. Here we reviewed recent advances in basic properties and clinical applications of ASO and siRNA, and provide future perspective on oligonucleotide therapeutics.

Cryptococcal meningitis accompanying lymphocytic inflammation predominantly in cerebral deep white matter: a possible manifestation of immune reconstitution inflammatory syndrome.

Cryptococcal meningitis is rarely complicated by immune-mediated leukoencephalopathy, but the precise pathomechanism is uncertain. A 72-year-old Japanese man treated with prednisolone for Sweet disease developed a subacute progression of meningitis, which was considered as neuro-Sweet disease. A treatment by methylprednisolone rapidly improved CSF findings with a remarkable decrease in lymphocyte numbers in the blood, but the patient's consciousness still worsened after the cessation of the treatment. The patient developed cryptococcal meningitis and MRI showed abnormal intensities predominantly in the cerebral deep white matter along with the recovery of lymphocyte numbers in the blood, which resulted in death. A postmortem examination of the brain revealed degenerative lesions, especially at the cerebral white matter and cortex adjacent to the leptomeninges abundantly infiltrated by Cryptococcus neoformans. In the affected cerebral deep white matter, perivascular infiltration of lymphocytes was prominent in coexistence with reactive astrocytes and vascular proliferation, but these findings were not observed in the subcortical and cortical lesions. Cryptococcus neoformans was not present within the brain parenchyma. This is the first report of a case suggesting that cryptococcal meningitis can accompany lymphocytic inflammation predominantly in cerebral deep white matter as a possible manifestation of immune reconstitution inflammatory syndrome.

[Peripheral Nerve and Muscle Disorders Associated with Sjögren's Syndrome].

Sjögren's syndrome is often accompanied by various neurological complications, among which peripheral neuropathy is the most common. A variety of clinical phenotypes of peripheral neuropathy, including axonal polyneuropathy and sensory ataxic neuropathy are reported in the literature. We present an overview of the pathophysiology and differential diagnosis of each phenotype. Immunotherapy using corticosteroids and high-dose intravenous immunoglobulin therapy tends to elicit varied therapeutic responses depending on the peripheral neuropathy phenotype. We also discuss myositis, a possible complication of Sjögren's syndrome.

Intraperitoneal administration of AAV9-shRNA inhibits target gene expression in the dorsal root ganglia of neonatal mice.

BACKGROUND: There is considerable interest in inducing RNA interference (RNAi) in neurons to study gene function and identify new targets for disease intervention. Although short interfering RNAs (siRNAs) have been used to silence genes in neurons, in vivo delivery of RNAi remains a major challenge, especially by systemic administration. We have developed a highly efficient method for in vivo gene silencing in dorsal root ganglia (DRG) by using short hairpin RNA-expressing single-stranded adeno-associated virus 9 (ssAAV9-shRNA). RESULTS: Intraperitoneal administration of ssAAV9-shRNA to neonatal mice resulted in highly effective and specific silencing of a target gene in DRG. We observed an approximately 80% reduction in target mRNA in the DRG, and 74.7% suppression of the protein was confirmed by Western blot analysis. There were no major side effects, and the suppression effect lasted for more than three months after the injection of ssAAV9-shRNA. CONCLUSIONS: Although we previously showed substantial inhibition of target gene expression in DRG via intrathecal ssAAV9-shRNA administration, here we succeeded in inhibiting target gene expression in DRG neurons via intraperitoneal injection of ssAAV9-shRNA. AAV9-mediated delivery of shRNA will pave the way for creating animal models for investigating the molecular biology of the mechanisms of pain and sensory ganglionopathies.

Efficient in vivo delivery of siRNA into brain capillary endothelial cells along with endogenous lipoprotein.

The brain capillary endothelial cell (BCEC) is a major functional component of the blood-brain barrier and is an underlying factor in the pathophysiology of various diseases, including brain ischemia, multiple sclerosis, and neurodegenerative disorders. We examined gene silencing in BCECs by using endogenous lipoprotein to introduce short-interfering RNA (siRNA) in vivo. A cholesterol-conjugated 21/23-mer siRNA targeting organic anion transporter 3 (OAT3) mRNA (Chol-siOAT3) was intravenously injected into mice after its incorporation into extracted endogenous lipoproteins. Chol-siOAT3 was not delivered to neurons or glia, but was successfully delivered into BCECs and resulted in a significant reduction of OAT3 mRNA levels when injected after its incorporation into high-density lipoprotein (HDL). Efficient delivery was not achieved, however, when Chol-siOAT3 was injected without any lipoproteins, or after its incorporation into low-density lipoprotein (LDL). Investigations in apolipoprotein E (ApoE)-deficient and LDL receptor (LDLR)-deficient mice revealed that the uptake of HDL-containing Chol-siOAT3 was mainly mediated by ApoE and LDLR in mice. These findings indicate that siRNA can be delivered into BCECs in vivo by using endogenous lipoprotein, which could make this strategy useful as a new gene silencing therapy for diseases involving BCECs.

[Career as a Technical Official at the Ministry of Health, Labour and Welfare for a Neurologist].

Technical officials with a medical doctor's license at the Ministry of Health, Labour and Welfare, who account for only about 0.1% of all medical doctors, are involved in administrative affairs requiring specialized knowledge and experience in health care. Here, I outline the situation in which a neurologist is seconded to the Ministry of Health, Labor and Welfare for personnel exchanges and works as a technical official, based on my own experience. Further, I also give my opinion on the advantages and disadvantages of this career move. I hope that this will encourage neurologists to think about the significance of their careers as technical officials at the Ministry of Health, Labour and Welfare.

Serial ultrathin sections to identify ultrastructural localization of GLUT1 molecules in vesicles in brain endothelial cells-correlative light and electron microscopy in depth.

Precise immunolocalization of molecules in relation to ultrastructural features is challenging, especially when the target is small and not frequent enough to be included in tiny ultrathin sections randomly selected for electron microscopy (EM). Glucose transporter 1 (GLUT1) is in charge of transporting glucose across brain capillary endothelial cells (BCECs). Paraformaldehyde-fixed floating sections (50 µm thick) of mouse brain were immunolabeled with anti-GLUT1 antibody and visualized with fluoronanogold. Fluorescent images encompassing the entire hemisphere were tiled to enable selection of GLUT1-positive BCECs suitable for subsequent EM and landmark placement with laser microdissection to guide trimming. Sections were then fixed with glutaraldehyde, gold enhanced to intensify the labeling and fixed with osmium tetroxide to facilitate ultrastructural recognition. Even though a region that contained target BCECs was successfully trimmed in the resin block, it was only after observation of serial ultrathin sections that GLUT1 signals in coated vesicles on the same cross section corresponding to the cross section preidentified by confocal laser microscope. This is the first ultrastructural demonstration of GLUT1 molecules in coated vesicles, which may well explain its functional relevance to transport glucose across BCECs. Successful ultrastructural localization of molecules in relation to well-preserved target structure in native tissue samples, as achieved in this study, will pave the way to understand the functional relevance of molecules and their relation to ultrastructural details.

Spinocerebellar Ataxia Type 31 Exacerbated by Anti-amino Terminal of Alpha-enolase Autoantibodies.

We herein report a 61-year-old woman who was genetically diagnosed with spinocerebellar ataxia type 31 whose symptoms were modified by anti-amino terminal of alpha-enolase (NAE) antibodies, known as a biomarker of Hashimoto's encephalopathy (HE), and ultimately responded to immunotherapy. The relative titers of anti-NAE antibodies increased when her cerebellar ataxia showed acute deterioration and decreased after immunotherapy. This is the first report of cerebellar ataxia associated with genetic spinocerebellar ataxia with concomitant cerebellar type HE. Physicians should be mindful of measuring anti-NAE antibodies to prevent overlooking patients with genetic spinocerebellar ataxia with treatable simultaneous ataxic diseases.

[Rapid progressive HTLV-1-associated myelopathy with bronchoalveolar lesions and a long spinal cord lesion extending to almost the entire spinal cord].

We report the case of a 73-year-old woman with progressive gait disturbance for several months and an impaired standing ability. Her symptoms were lower-limb-dominant spastic tetraplegia with normal muscle tonus, hyperreflexia with positive Babinski sign, hypothermesthesia and hypalgesia in bilateral lower limbs, and dysesthesia in the fingers of both hands. Magnetic resonance (MR) images revealed a long lesion extending to nearly the entire spinal cord, and chest computed tomography (CT) revealed diffuse multiple small nodular lesions in the lower parts of the right and left lungs. High titers of human T-cell lymphotropic virus (HTLV)-1 antibodies in the serum and CSF, large amount of HTLV-1 provirus and neopterin in the CSF, and lymphocytic infiltration around bronchioles in pulmonary biopsy specimens indicated the presence of HTLV-1-associated myelopathy (HAM) with HTLV-1-associated bronchiolo-alveolar disorder (HABA). Her neurologic symptoms and the lesions in the spinal cord and lungs rapidly improved after corticosteroid pulse therapy. Rapid progressive HAM should be considered as a differential diagnosis of subacute spastic paraparesis with long spinal cord lesions. Further, careful investigation to detect pulmonary lesions, which are reported to be asymptomatic in most cases, is useful to confirm a diagnosis of HAM.

Highly efficient gene silencing in mouse brain by overhanging-duplex oligonucleotides via intraventricular route.

Gapmer-type antisense oligonucleotides have not yet been approved for the treatment of central nervous system diseases, whereas steric-blocking-type antisense oligonucleotides have been well-developed for clinical use. We here characterize a new type of double-stranded oligonucleotides, overhanging-duplex oligonucleotides, which are composed of the parent gapmer and its extended complementary RNA. By intracerebroventricular injection, overhanging oligonucleotides show greater silencing potency with more efficient delivery into mouse brains than the parent single-stranded gapmer. Structure-activity relationship analyses reveal that the potency enhancement requires 13-mer or more overhanging oligonucleotides with a phosphorothioate backbone. Overhanging oligonucleotides provide a new platform of therapeutic oligonucleotides for gene modulation in the central nervous system.

Intrathecal IgG Synthesis and Persistent Inflammation Are Associated with White Matter Lesions in HIV-negative Patients with Cryptococcal Meningoencephalitis.

Objective Cryptococcal meningoencephalitis (CM) causes significant morbidity and mortality in human immunodeficiency virus (HIV)-negative and HIV-positive populations. White matter lesions (WMLs) have been reported in both populations of CM patients; however, the mechanisms underlying WML formation remain unknown. We herein report the relationship between the intrathecal immune response and the development of WMLs in HIV-negative patients with CM. Methods Eleven consecutive HIV-negative patients with CM who presented at one of three emergency hospitals in Japan from April 2001 to March 2018 were enrolled. For all patients, we retrospectively assessed the relationships between clinical and laboratory information and the presence of WMLs. Results At presentation, 6 patients had WMLs on magnetic resonance imaging (MRI). The cerebrospinal fluid immunoglobulin G (CSF IgG) index was significantly higher in the patients with WMLs than in those without WMLs (mean, 1.34 vs. 0.70, p=0.017). The time from the symptom onset to initial neuroimaging was also significantly longer in the patients with WMLs than in those without WMLs (median, 31.5 vs. 7.0 days; p=0.008). The clinical outcome was comparable among the patients with and without WMLs. Conclusion In HIV-negative patients with CM, a persistent, aberrant immune response to Cryptococcus, such as intrathecal IgG synthesis, may induce WML formation.

[Case of an 81-year-old woman with theophylline-associated seizures followed by partial seizures due to vitamin B6 deficiency].

We report an 81-year-old woman who suffered from theophylline-associated seizures followed by partial seizures due to vitamin B6 deficiency. She developed complex partial seizures. She had been treated with theophylline for two months because of chronic bronchitis. Brain diffusion-weighted magnetic resonance imaging (MRI) showed high intensity lesions in unilateral cerebral cortex and thalamus. Electroencephalogram presented periodic lateralized epileptiform discharges (PLEDs), and single photon emission computed tomography (SPECT) using 123I-IMP revealed increased blood flow in the same side of the cerebrum. We diagnosed as theophylline-associated seizures though blood theophylline concentration disclosed its therapeutic dose, and her symptom improved after theophylline was discontinued. She developed partial seizures again, after she suffered from diarrhea for two days. Laboratory examination showed that serum vitamin B6 was under the limitation of measurement, and intravenous supplementation of vitamin B6 stopped her seizures immediately. Theophylline may induce seizures independent of its blood concentration, and vitamin B6 deficiency may exist in the case of theophylline-associated seizures.

Modulation of blood-brain barrier function by a heteroduplex oligonucleotide in vivo.

The blood-brain barrier (BBB) is increasingly regarded as a dynamic interface that adapts to the needs of the brain, responds to physiological changes, and gets affected by and can even promote diseases. Modulation of BBB function at the molecular level in vivo is beneficial for a variety of basic and clinical studies. Here we show that our heteroduplex oligonucleotide (HDO), composed of an antisense oligonucleotide and its complementary RNA, conjugated to α-tocopherol as a delivery ligand, efficiently reduced the expression of organic anion transporter 3 (OAT3) gene in brain microvascular endothelial cells in mice. This proof-of-concept study demonstrates that intravenous administration of chemically synthesized HDO can remarkably silence OAT3 at the mRNA and protein levels. We also demonstrated modulation of the efflux transport function of OAT3 at the BBB in vivo. HDO will serve as a novel platform technology to advance the biology and pathophysiology of the BBB in vivo, and will also open a new therapeutic field of gene silencing at the BBB for the treatment of various intractable neurological disorders.

Angubindin-1 opens the blood-brain barrier in vivo for delivery of antisense oligonucleotide to the central nervous system.

Within the field of RNA therapeutics, antisense oligonucleotide-based therapeutics are a potentially powerful means of treating intractable diseases. However, if these therapeutics are used for the treatment of neurological disorders, safe yet efficient methods of delivering antisense oligonucleotides across the blood-brain barrier to the central nervous system must be developed. Here, we examined the use of angubindin-1, a binder to the tricellular tight junction, to modulate paracellular transport between brain microvascular endothelial cells in the blood-brain barrier for the delivery of antisense oligonucleotides to the central nervous system. This proof-of-concept study demonstrated that intravenously injected angubindin-1 increased the permeability of the blood-brain barrier and enabled transient delivery of subsequently administered antisense oligonucleotides into the mouse brain and spinal cord, leading to silencing of a target RNA without any overt adverse effects. We also found that two bicellular tight junction modulators did not produce such a silencing effect, suggesting that the tricellular tight junction is likely a better target for the delivery of antisense oligonucleotides than the bicellular tight junction. Our delivery strategy of modulating the tricellular tight junction in the blood-brain barrier via angubindin-1 provides a novel avenue of research for the development of antisense oligonucleotide-based therapeutics for the treatment of neurological disorders.

Hypoglycemia and hyperglycemia due to insulin antibodies against therapeutic human insulin: treatment with double filtration plasmapheresis and prednisolone.

Two diabetic patients, who had been treated with human insulin, suffered from fasting hypoglycemia and postprandial hyperglycemia. The insulin-binding capacities of their sera were high, and a large amount of total insulin and prolonged presence of free insulin in the sera were shown. Scatchard analysis of these insulin antibodies revealed that high-affinity insulin antibodies had larger capacity and stronger affinity compared with commonly insulin-treated patients. Treatment with double filtration plasmapheresis and subsequent administration of prednisolone in the second patient reduced such antibodies and resulted in recovery of glycemic control by insulin. Hypoglycemia and hyperglycemia could be incurred when insulin antibodies with strong affinity and high capacity in high-affinity sites arise. This condition can be treated with double filtration plasmapheresis and subsequent administration of prednisolone.

Chimeric Antisense Oligonucleotide Conjugated to α-Tocopherol.

We developed an efficient system for delivering short interfering RNA (siRNA) to the liver by using α-tocopherol conjugation. The α-tocopherol-conjugated siRNA was effective and safe for RNA interference-mediated gene silencing in vivo. In contrast, when the 13-mer LNA (locked nucleic acid)-DNA gapmer antisense oligonucleotide (ASO) was directly conjugated with α-tocopherol it showed markedly reduced silencing activity in mouse liver. Here, therefore, we tried to extend the 5'-end of the ASO sequence by using 5'-α-tocopherol-conjugated 4- to 7-mers of unlocked nucleic acid (UNA) as a "second wing." Intravenous injection of mice with this α-tocopherol-conjugated chimeric ASO achieved more potent silencing than ASO alone in the liver, suggesting increased delivery of the ASO to the liver. Within the cells, the UNA wing was cleaved or degraded and α-tocopherol was released from the 13-mer gapmer ASO, resulting in activation of the gapmer. The α-tocopherol-conjugated chimeric ASO showed high efficacy, with hepatic tropism, and was effective and safe for gene silencing in vivo. We have thus identified a new, effective LNA-DNA gapmer structure in which drug delivery system (DDS) molecules are bound to ASO with UNA sequences.