Unique clinical and electrophysiological features in the peripheral nerve system in patients with sialidosis - a case series study.

BACKGROUND: To investigate the peripheral nervous system involvement in S sialidosis with typical features of myoclonus, seizure, and giant waves in somatosensory evoked potentials suggesting hyperexcitability in the central nervous system. METHODS: The clinical presentation of patients with genetically confirmed sialidosis was recorded. Neurophysiological studies, including nerve conduction studies (NCSs), F-wave studies, and needle electromyography (EMG), were performed on these patients. RESULTS: Six patients (M/F: 2:4) were recruited. In addition to the classical presentation, intermittent painful paresthesia was noted in four patients, and three of whom reported it as the earliest symptom. In the NCSs, one patient had reduced compound muscle action potential amplitudes in the right ulnar nerve, while another patient had prolonged distal motor latency in the bilateral tibial and peroneal nerves. Prolonged F-wave latency (83.3%), repeater F-waves (50%), and neurogenic polyphasic waves in EMG (in 2 out of 3 examined patients) were also noted. Interestingly, a very late response was noted in the F-wave study of all patients, probably indicating lesions involving the proximal peripheral nerve or spinal cord. CONCLUSION: In addition to the central nervous system, the peripheral nervous system is also involved in sialidosis, with corresponding clinical symptoms. Further study on these phenomena is indicated.

Biophysical mechanisms underlying tefluthrin-induced modulation of gating changes and resurgent current generation in the human Nav1.4 channel.

Human skeletal muscle contraction is triggered by activation of Nav1.4 channels. Nav1.4 channels can generate resurgent currents by channel reopening at hyperpolarized potentials through a gating transition dependent on the intracellular Navß4 peptide in the physiological conditions. Tefluthrin (TEF) is a pyrethroid insecticide that can disrupt electrical signaling in nerves and skeletal muscle, resulting in seizures, muscle spasms, fasciculations, and mental confusion. TEF can also induce tail currents through other voltage-gated sodium channels in the absence of Navß4 peptide, suggesting that muscle spasms may be caused by resurgent currents. Further, intracellular Navß4 peptide and extracellular TEF may show competitive or synergistic effects; however, their binding sites are still unknown. To address these issues, electrophysiological recordings were performed on CHO-K1 cells expressing Nav1.4 channels with intracellular Navß4 peptide, extracellular TEF, or both. TEF and Navß4 peptide induced a hyperpolarizing shift of activation and inactivation curves in the Nav1.4 channel. TEF also substantially prolonged the inactivation time constants, while simultaneous application of Navß4 peptide partially reversed this effect. Resurgent currents were enhanced by TEF and Navß4 peptide at negative potentials, but TEF more potently enhances resurgent currents and dampens decay of resurgent currents. With longer depolarization, peak resurgent currents decay was fastest with the TEF alone. Molecular docking suggested that TEF and Navß4 peptide binding site(s) are not in the narrowest part of the channel pore, but rather in the bundle-crossing regions and in the domain linkers, respectively. TEF can induce resurgent currents independently and synergistically with Navß4 peptide, which may explain the muscle spasms observed in TEF intoxication.

Patisiran, an RNAi therapeutic for hereditary transthyretin-mediated amyloidosis: Sub-analysis in Taiwanese patients from the APOLLO study.

BACKGROUND AND OBJECTIVES: To examine the efficacy and safety of patisiran, an RNA interference therapeutic, in patients from Taiwan with hereditary transthyretin-mediated (hATTR) amyloidosis with polyneuropathy. METHODS: The APOLLO phase 3 trial included patients from Taiwan who received patisiran 0.3 mg/kg intravenously or placebo once every 3 weeks (q3w) for 18 months (18 M), followed by patisiran 0.3 mg/kg q3w in an ongoing global open-label extension (OLE) study. The primary endpoint was change from baseline in modified Neuropathy Impairment Score +7 (mNIS+7) at 18 M. RESULTS: Eighteen Taiwanese patients were enrolled in APOLLO (patisiran, n = 8; placebo, n = 10; all A97S gene variant) and 14 continued in the global OLE. In this Taiwanese sub-population, beneficial treatment effects at 18 M were observed in mNIS+7 (least squares mean difference in change from baseline [patisiran-placebo], -26.5 points; 95% confidence interval: -45.5, -7.5). Patients who switched from placebo to patisiran demonstrated slowing of polyneuropathy progression at month 12 in the global OLE, while those who received patisiran in APOLLO maintained the beneficial treatment effects. Patisiran had an acceptable safety profile in the Taiwanese sub-population. CONCLUSIONS: This analysis suggests that patisiran is well tolerated and may provide a substantial clinical benefit for Taiwanese patients with hATTR amyloidosis with polyneuropathy. TRIAL REGISTRATION INFORMATION: The studies were registered on the ClinicalTrials.gov. The APOLLO study ClinicalTrials.gov identifier is NCT01960348 (https://clinicaltrials.gov/ct2/show/NCT01960348), with the registration date of October 10, 2013, and the first patient was enrolled on December 13, 2013. For the global OLE, the ClinicalTrials.gov identifier is NCT02510261 (https://clinicaltrials.gov/ct2/show/NCT02510261) with the registration date of July 29, 2015, and the first patient was enrolled on July 13, 2015. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that treatment with patisiran is safe and efficacious in Taiwanese patients with hereditary transthyretin-mediated amyloidosis with polyneuropathy.

Tafamidis improves myocardial longitudinal strain in A97S transthyretin cardiac amyloidosis.

Background: Transthyretin cardiomyopathy (ATTR-CM) is a debilitating disease that has received much attention since the emergence of novel treatments. The Transthyretin Cardiomyopathy Clinical Trial showed that tafamidis, a transthyretin tetramer stabilizer, effectively reduced the declines in functional capacity and quality of life. However, Ala97Ser (A97S) hereditary ATTR-CM is underrepresented in major ATTR-CM tafamidis trials. Objectives: We aim to investigate the change in global longitudinal strain (GLS) of A97S ATTR-CM patients after 12 months of tafamidis treatment. Methods: We retrospectively analysed a prospective cohort of patients with A97S ATTR-CM who received tafamidis meglumine (61 mg/day) at the National Taiwan University Hospital. Echocardiography with speckle tracking strain analysis was performed at baseline and 12 months after treatment. Results: In all, 20 patients were included in the cohort. The baseline left ventricular ejection fraction (LVEF) and interventricular septum (IVS) thickness were 59.20 ± 13.23% and 15.10 ± 3.43 mm, respectively. After 12 months of tafamidis treatment, the LVEF and IVS were 61.83 ± 15.60% (p = 0.244) and 14.59 ± 3.03 mm (p = 0.623), respectively. GLS significantly improved from -12.70 ± 3.31% to -13.72 ± 3.17% (p = 0.048), and longitudinal strain (LS) in apical and middle segments significantly improved from -16.05 ± 4.82% to -17.95 ± 3.48% (p = 0.039) and -11.89 ± 4.38% to -13.58 ± 3.12% (p = 0.039), respectively. Subgroup analysis showed that patients with LVEF < 50% had a better treatment response and improvement in GLS. The patients with an IVS ⩾ 13 mm had an improvement in two-chamber LS from -10.92 ± 4.25% to -13.15 ± 3.87% (p = 0.042) and an improvement in apical left ventricular LS from -15.30 ± 5.35% to -17.82 ± 3.99% (p = 0.031). Conclusion: Tafamidis significantly improved GLS, and particularly apical and middle LS in A97S ATTR-CM patients.

Tafamidis improves myocardial longitudinal strain in A97S transthyretin cardiac amyloidosis Transthyretin cardiomyopathy (ATTR-CM) is a severe heart condition that has gained attention due to recent advancements in treatments. One of these treatments, called tafamidis, has been shown to be effective in maintaining heart function and quality of life. However, there has been limited research on a specific genetic variation of ATTR-CM: A97S. Our aim was to determine whether A97S ATTR-CM patients experienced improved heart function after one year of tafamidis treatment. We conducted this study at the National Taiwan University Hospital, where we enrolled 20 A97S ATTR-CM patients. We used echocardiography to evaluate their heart function, focusing on a parameter called global longitudinal strain. The results showed that after one year of tafamidis treatment, these patients experienced a significant improvement in their global longitudinal strain, particularly in the apical and middle regions of the heart. In conclusion, tafamidis appears to be beneficial for A97S ATTR-CM patients by enhancing their heart's global longitudinal strain, which is a positive sign for their cardiac health.

Use of Technetium-99m-Pyrophosphate Single-Photon Emission Computed Tomography/Computed Tomography in Monitoring Therapeutic Changes of Eplontersen in Patients With Hereditary Transthyretin Amyloid Cardiomyopathy.

BACKGROUND: Hereditary transthyretin amyloid cardiomyopathy (hATTR-CM) is a progressive and fatal disease. Recent evidence indicates that bone scintigraphy may serve as a tool to monitor the effectiveness of hATTR-CM treatment. The objective of this study was to examine how eplontersen therapy influences the semiquantitative uptake of technetium-99m-pyrophosphate in individuals diagnosed with hATTR-CM. METHODS AND RESULTS: We retrospectively analyzed a prospective cohort from the NEURO-TTRansform trial, including patients with hATTR-CM receiving eplontersen (45 mg/4 weeks). A control group comprised patients with hATTR-CM who had not received eplontersen, inotersen, tafamidis, or patisiran. Technetium-99m-pyrophosphate single-photon emission computed tomography/computed tomography was conducted at baseline and during follow-up. Thirteen patients with hATTR-CM were enrolled, with 6 receiving eplontersen and 7 serving as the control group. The median follow-up time was 544 days. The eplontersen group exhibited a significant decrease in volumetric heart and lung ratio (3.774 to 2.979, P=0.028), whereas the control group showed no significant change (4.079 to 3.915, P=0.237). Patients receiving eplontersen demonstrated a significantly greater reduction in volumetric heart and lung ratio compared with the control group (-20.7% versus -3.4%, P=0.007). CONCLUSIONS: The volumetric heart and lung ratio used to quantify technetium-99m-pyrophosphate uptake showed a significant reduction subsequent to eplontersen treatment in individuals diagnosed with hATTR-CM. These findings suggest the potential efficacy of eplontersen in treating hATTR-CM and highlight the value of technetium-99m-pyrophosphate single-photon emission computed tomography/computed tomography as a tool for monitoring therapeutic effectiveness.

A randomized, placebo-controlled study of givosiran in patients with acute hepatic porphyrias (ENVISION): Final (36-month) analysis of the Taiwan Cohort.

BACKGROUND/PURPOSE: Acute hepatic porphyrias (AHP) are rare genetic disorders associated with acute neurovisceral attacks and chronic symptoms. This analysis was conducted to examine the long-term efficacy and safety of givosiran in Taiwanese participants in the ENVISION study (NCT03338816). METHODS: Patients (age ≥12 years) with AHP and recurrent attacks were randomized to receive givosiran 2.5 mg/kg or placebo for 6 months during the double-blind period. Patients then switched from placebo to givosiran (placebo crossover group) or continued taking givosiran (continuous givosiran group) during a 30-month open-label extension period. The total study duration was 36 months. An analysis was conducted that included patients enrolled in Taiwan (N = 7). RESULTS: During the double-blind period and open-label extension period, the median annualized attack rates were 0.0 and 0.0, respectively, in the continuous givosiran group (n = 5) and 15.1 and 4.6, respectively, in the placebo crossover group (n = 2; 70 % decrease). Median annualized days of hemin use in the double-blind period and open-label extension period were 0.0 and 0.0, respectively, in the continuous givosiran group, and 23.8 and 5.0, respectively, in the placebo crossover group (79 % decrease). EQ-5D VAS scores remained relatively stable in both groups, and PPEQ responses indicated improved functioning and satisfaction in both groups. Delta-aminolevulinic acid and porphobilinogen levels remained low with long-term givosiran treatment. Serious adverse events were reported by 3 patients (43 %). CONCLUSIONS: Long-term efficacy and safety results in the Taiwan cohort are consistent with those in the global cohort.

Growth of B16F10 cells is enhanced in DJ-1-deficiency pancreas.

Association between cancer risk and Parkinson's disease is still debated. DJ-1, a Parkinson's disease (PD)-related gene, is encoded by PARK-7 gene and its deficiency causes early-onset PD. In our last studies, it was found that the immunosuppressive microenvironment established in DJ-1 knockout (KO) mice can enhance metastasis of melanoma cells to lungs. Therefore, we wanted to further examine whether there were some niche in other organs of DJ-1-deficiency mouse to facilitate cell growth of tumors. We used in vivo tissue-specific models of tumor growth and in vitro cellular model to verify the hypothesis. We also used protein blot assay, cell-adhesion assay and bioinformatic tools to conduct experiments. In the mouse model of subcutaneous injection, there was no difference on tumor growth between WT and DJ-1 KO mice. Moreover, the results of experimental liver metastasis by intrasplenic injection model showed that there was no difference of nodules number in both mice, but a dramatic enhancement of nodule formation and increased mucin4 levels were found in pancreas of DJ-1 KO mice. In cell cultures, we further found that B16F10 cells indeed tended to adhere well to primary DJ-1-deficiency pancreatic epithelial cells, which had higher protein levels of mucin4. Notably, a human database also showed the inverse relationship in human pancreas between DJ-1 and mucin4, and mucin4 down-regulation can reverse the enhanced cellular adhesion in DJ-1 KO pancreatic epithelial cells. These results indicated that DJ-1 KO pancreatic tissue creating an appropriate microenvironment benefited development of the cancer cells.

Tafamidis decreased cardiac amyloidosis deposition in patients with Ala97Ser hereditary transthyretin cardiomyopathy: a 12-month follow-up cohort study.

BACKGROUND: Transthyretin cardiac cardiomyopathy (ATTR-CM) is a rare but life-threatening disease. Tafamidis is an effective treatment for patients with ATTR-CM, however its long-term effects on cardiac remodeling and cardiac amyloid deposition are unknown. This study aimed to used cardiac magnetic resonance (CMR) to investigate the effects of tafamidis on patients with hereditary A97S ATTR-CM. METHODS: We retrospectively analyzed a prospective cohort of ATTR-CM patients, including 14 with hereditary A97S ATTR-CM and 17 healthy controls with baseline CMR data. All ATTR-CM patients received tafamidis treatment and received CMR with extracellular volume (ECV) at baseline and after 1 year of follow-up. RESULTS: Baseline N-terminal pro-B-type natriuretic peptide, left ventricular (LV) mass, LV ejection fraction, global radial, circumferential and longitudinal strain, T1 mapping and ECV were significantly worse in the patients with ATTR-CM compared with the healthy controls. After 1 year of tafamidis treatment, ECV decreased from 51.5 ± 8.9% to 49.0 ± 9.4% (P = 0.041), however there were no significant changes in LV mass, LV ejection fraction, global radial strain, global circumferential strain, global longitudinal strain and T1 mapping. CONCLUSIONS: After a one-year treatment period, tafamidis exhibited subtle but statistically significant reductions in ECV, potentially indicating a decrease in amyloid deposition among patients diagnosed with hereditary A97S ATTR-CM.

Efficacy of Tafamidis in Patients with Ala97Ser Hereditary Transthyretin Cardiac Amyloidosis: A Six-Month Follow-Up Study.

Background: Hereditary transthyretin amyloid cardiomyopathy (ATTR-CM) is a progressive and fatal disease. A97S (p.Ala117Ser) is the most common transthyretin genetic mutation in Taiwan. Tafamidis is a transthyretin stabilizer, and it has been shown to improve outcomes. However, its effect on A97S ATTR-CM subtypes remains unknown. Objectives: This study aimed to investigate the efficacy of tafamidis in patients with hereditary A97S ATTR-CM after 6 months of treatment. Methods: We retrospectively analyzed ATTR-CM patients who received tafamidis (61 mg/day) treatment at National Taiwan University Hospital. Functional status, biochemistry and echocardiography were measured at baseline and after 6 months of tafamidis treatment. The outcome measure was to compare the N-terminal pro-brain natriuretic peptide (NT-proBNP) level at baseline and after 6 months of tafamidis treatment. Results: Twenty patients were enrolled in this study. Their mean age was 63.0 ± 5.8 years and 75% were men. The baseline left ventricular (LV) mass index was 200.9 ± 63.9 g/m2, and the baseline LV ejection fraction was 58.9 ± 13.5%. After 6 months of treatment, the log NT-proBNP level significantly improved from 2.9 ± 0.6 to 2.7 ± 0.5 (p = 0.036). Subgroup analysis showed that the LV posterior wall thickness and left atrial diameter were significantly higher in the patients with improved NT-proBNP, suggesting the benefits of tafamidis for ATTR-CM patients with severe cardiac involvement. Conclusions: The patients with hereditary A97S ATTR-CM in this study had decreased levels of NT-proBNP after 6 months of tafamidis treatment, and this reduction was especially pronounced in those with more severe cardiac involvement.

FT895 Impairs Mitochondrial Function in Malignant Peripheral Nerve Sheath Tumor Cells.

Neurofibromatosis type 1 (NF1) stands as a prevalent neurocutaneous disorder. Approximately a quarter of NF1 patients experience the development of plexiform neurofibromas, potentially progressing into malignant peripheral nerve sheath tumors (MPNST). FT895, an HDAC11 inhibitor, exhibits potent anti-tumor effects on MPNST cells and enhances the cytotoxicity of cordycepin against MPNST. The study aims to investigate the molecular mechanism underlying FT895's efficacy against MPNST cells. Initially, our study unveiled that FT895 disrupts mitochondrial biogenesis and function. Post-FT895 treatment, reactive oxygen species (ROS) in MPNST notably increased, while mitochondrial DNA copy numbers decreased significantly. Seahorse analysis indicated a considerable decrease in basal, maximal, and ATP-production-coupled respiration following FT895 treatment. Immunostaining highlighted FT895's role in promoting mitochondrial aggregation without triggering mitophagy, possibly due to reduced levels of XBP1, Parkin, and PINK1 proteins. Moreover, the study using CHIP-qPCR analysis revealed a significant reduction in the copy numbers of promoters of the MPV17L2, POLG, TFAM, PINK1, and Parkin genes. The RNA-seq analysis underscored the prominent role of the HIF-1α signaling pathway post-FT895 treatment, aligning with the observed impairment in mitochondrial respiration. In summary, the study pioneers the revelation that FT895 induces mitochondrial respiratory damage in MPNST cells.

EXPLORE B: A prospective, long-term natural history study of patients with acute hepatic porphyria with chronic symptoms.

One-year data from EXPLORE Part A showed high disease burden and impaired quality of life (QOL) in patients with acute hepatic porphyria (AHP) with recurrent attacks. We report baseline data of patients who enrolled in EXPLORE Part B for up to an additional 3 years of follow-up. EXPLORE B is a long-term, prospective study evaluating disease activity, pain intensity, and QOL in patients with AHP with ≥1 attack in the 12 months before enrollment or receiving hemin or gonadotropin-releasing hormone prophylaxis. Data were evaluated in patients with more (≥3 attacks or on prophylaxis treatment) or fewer (<3 attacks and no prophylaxis treatment) attacks. Patients in the total population (N = 136), and more (n = 110) and fewer (n = 26) attack subgroups, reported a median (range) of 3 (0-52), 4 (0-52), and 1 (0-2) acute attacks, respectively, in the 12 months prior to the baseline visit. Pain, mood/sleep, digestive/bladder, and nervous system symptoms were each experienced by ≥80% of patients; most received hemin during attacks. Almost three-quarters of patients reported chronic symptoms between attacks, including 85% of patients with fewer attacks. Pain intensity was comparable among both attack subgroups; most patients required pain medication. All groups had diminished QOL on the EuroQol visual analog scale and the European Organisation for Research and Treatment of Cancer Quality-of-life Questionnaire Core 30 versus population norms. Patients with AHP with recurrent attacks, even those having fewer attacks, experience a high disease burden, as evidenced by chronic symptoms between attacks and impaired QOL.

Comparison of clinical and neuroimaging features between NOTCH3 mutations and nongenetic spontaneous intracerebral haemorrhage.

BACKGROUND AND PURPOSE: The NOTCH3 mutation is a common cause of hereditary cerebral small vessel disease (CSVD) and may be a cause of spontaneous intracerebral haemorrhage (ICH). The aim was to investigate the clinical/imaging features for identifying the NOTCH3-mutation-related ICH. METHODS: The study was based on a cohort of 749 CSVD patients in Taiwan who received next-generation sequencing of CSVD genes including NOTCH3. Patients with a history of ICH (n = 206) were included for analysis. The CSVD neuroimaging markers were compared between the patients with NOTCH3 and those without known genetic mutations. RESULTS: After excluding patients with other causes of ICH (structural lesions, systemic/medication related or amyloid angiopathy) and those without neuroimaging, 45 NOTCH3 mutation patients and 109 nongenetic ICH patients were included. The NOTCH3 mutation patients were more likely to have thalamic haemorrhage, a family history of stroke and more severe CSVD neuroimaging markers. A five-point NOTCH3-ICH score was constructed and consisted of a history of stroke in siblings, thalamic haemorrhage, any deep nuclei lacunae, any hippocampal cerebral microbleed (CMB) and a thalamic CMB >5 (one point for each). A score ≥2 had a sensitivity of 88.9% and a specificity of 64.2% in identifying the NOTCH3 mutation. The NOTCH3 mutation patients had a higher risk of recurrent stroke (9.1 vs. 4.5 per 100 person-years, log-rank p = 0.03) during follow-up. CONCLUSION: The patients with NOTCH3-mutation-related ICH had a higher burden of CMBs in the hippocampus/thalamus and a higher recurrent stroke risk. The NOTCH3-ICH score may assist in identifying genetic causes of ICH.

Kinetic Alterations in Resurgent Sodium Currents of Mutant Nav1.4 Channel in Two Patients Affected by Paramyotonia Congenita.

Paramyotonia congenita (PMC) is a rare skeletal muscle disorder characterized by muscle stiffness upon repetitive exercise and cold exposure. PMC was reported to be caused by dominant mutations in the SCN4A gene encoding the α subunit of the Nav1.4 channel. Recently, we identified two missense mutations of the SCN4A gene, p.V781I and p.A1737T, in two PMC families. To evaluate the changes in electrophysiological properties caused by the mutations, both mutant and wild-type (WT) SCN4A genes were expressed in CHO-K1 and HEK-293T cells. Then, whole-cell patch-clamp recording was employed to study the altered gating of mutant channels. The activation curve of transient current showed a hyperpolarizing shift in both mutant Nav1.4 channels as compared to the WT channel, whereas there was a depolarizing shift in the fast inactivation curve. These changes confer to an increase in window current in the mutant channels. Further investigations demonstrated that the mutated channel proteins generate significantly larger resurgent currents as compared to the WT channel and take longer to attain the peak of resurgent current than the WT channel. In conclusion, the current study demonstrates that p.V781I and p.A1737T mutations in the Nav1.4 channel increase both the sustained and the resurgent Na+ current, leading to membrane hyperexcitability with a lower firing threshold, which may influence the clinical phenotype.

A novel HDAC11 inhibitor potentiates the tumoricidal effects of cordycepin against malignant peripheral nerve sheath tumor through the Hippo signaling pathway.

Neurofibromatosis type 1 (NF1) is an autosomal dominant neurocutaneous disorder. Clinically, the hallmarks of NF1 include skin pigmentation and cutaneous neurofibroma. Some NF1 patients develop plexiform neurofibroma (PN) since early childhood. Pathologically, PN contains abundant Schwann cells, blood vessels and connective tissues, which may transform into a malignant peripheral nerve sheath tumor (MPNST). MPNST is a highly invasive sarcoma without any effective therapy. Recently, both in vitro and in vivo studies showed that cordycepin can inhibit the growth of MPNST cells. Cordycepin causes cell cycle arrest at G2/M phase and downregulates the protein levels of α-tubulin, p53 and Sp1. Herein, the present study revealed that the HDAC11 inhibitor, FT895, can synergistically enhance the tumoricidal effect of cordycepin against MPNST cells in vitro. Treatment with the combination of cordycepin and FT895 reduced the size of MPNST in the xenograft mouse model. The combined treatment decreased the protein levels of α-tubulin and KIF18A, which may disrupt the microtubule organization leading to the mis-segregation of chromosomes and aneuploidy. Moreover, the expression levels of TEAD1 and its co-activator TAZ, the candidate proteins in hippo signaling pathway, were suppressed after combined treatment. Sequence analysis found a few binding sites for the transcription factor, TEAD1 in the promoter regions of TUBA1B, KIF18A, TEAD1, TAZ, YAP, TP53 and SP1 genes. ChIP-qPCR assay showed that the combined treatment decreases the binding of TEAD1 to the promoters of TUBA1B, KIF18A, TEAD1, TAZ and YAP genes in STS26T cells. The reduced binding to TP53 and SP1 promoters was also found in S462TY cells, which was further confirmed by immunoblotting. The down-regulation of these important transcriptional factors may contribute to the vulnerability of MPNST. In summary, HDAC11 inhibitor, FT895 can potentiate the tumoricidal effect of cordycepin to suppress the MPNST cell growth, which was probably mediated by the dysfunction of hippo-signaling pathway.

Recent Advances in RNA Therapy and Its Carriers to Treat the Single-Gene Neurological Disorders.

The development of new sequencing technologies in the post-genomic era has accelerated the identification of causative mutations of several single gene disorders. Advances in cell and animal models provide insights into the underlining pathogenesis, which facilitates the development and maturation of new treatment strategies. The progress in biochemistry and molecular biology has established a new class of therapeutics-the short RNAs and expressible long RNAs. The sequences of therapeutic RNAs can be optimized to enhance their stability and translatability with reduced immunogenicity. The chemically-modified RNAs can also increase their stability during intracellular trafficking. In addition, the development of safe and high efficiency carriers that preserves the integrity of therapeutic RNA molecules also accelerates the transition of RNA therapeutics into the clinic. For example, for diseases that are caused by genetic defects in a specific protein, an effective approach termed "protein replacement therapy" can provide treatment through the delivery of modified translatable mRNAs. Short interference RNAs can also be used to treat diseases caused by gain of function mutations or restore the splicing aberration defects. Here we review the applications of newly developed RNA-based therapeutics and its delivery and discuss the clinical evidence supporting the potential of RNA-based therapy in single-gene neurological disorders.

Cannabidiol Selectively Binds to the Voltage-Gated Sodium Channel Nav1.4 in Its Slow-Inactivated State and Inhibits Sodium Current.

Cannabidiol (CBD), one of the cannabinoids from the cannabis plant, can relieve the myotonia resulting from sodium channelopathy, which manifests as repetitive discharges of muscle membrane. We investigated the binding kinetics of CBD to Nav1.4 channels on the muscle membrane. The binding affinity of CBD to the channel was evaluated using whole-cell recording. The CDOCKER program was employed to model CBD docking onto the Nav1.4 channel to determine its binding sites. Our results revealed no differential inhibition of sodium current by CBD when the channels were in activation or fast inactivation status. However, differential inhibition was observed with a dose-dependent manner after a prolonged period of depolarization, leaving the channel in a slow-inactivated state. Moreover, CBD binds selectively to the slow-inactivated state with a significantly faster binding kinetics (>64,000 M-1 s-1) and a higher affinity (Kd of fast inactivation vs. slow-inactivation: >117.42 µM vs. 51.48 µM), compared to the fast inactivation state. Five proposed CBD binding sites in a bundle crossing region of the Nav1.4 channels pore was identified as Val793, Leu794, Phe797, and Cys759 in domain I/S6, and Ile1279 in domain II/S6. Our findings imply that CBD favorably binds to the Nav1.4 channel in its slow-inactivated state.

DNA Hypermethylation Involves in the Down-Regulation of Chloride Intracellular Channel 4 (CLIC4) Induced by Photodynamic Therapy.

The altered expression of chloride intracellular channel 4 (CLIC4) was reported to correlate with tumor progression. Previously, we have shown that the reduced cellular invasion induced by photodynamic therapy (PDT) is associated with suppression of CLIC4 expression in PDT-treated cells. Herein, we attempted to decipher the regulatory mechanisms involved in PDT-mediated CLIC4 suppression in A375 and MDA-MB-231 cells in vitro. We found that PDT can increase the expression and enzymatic activity of DNA methyltransferase 1 (DNMT1). Bisulfite sequencing PCR further revealed that PDT can induce hypermethylation in the CLIC4 promoter region. Silencing DNMT1 rescues the PDT-induced CLIC4 suppression and inhibits hypermethylation in its promoter. Furthermore, we found tumor suppressor p53 involves in the increased DNMT1 expression of PDT-treated cells. Finally, by comparing CLIC4 expression in lung malignant cells and normal lung fibroblasts, the extent of methylation in CLIC4 promoter was found to be inversely proportional to its expression. Taken together, our results indicate that CLIC4 suppression induced by PDT is modulated by DNMT1-mediated hypermethylation and depends on the status of p53, which provides a possible mechanistic basis for regulating CLIC4 expression in tumorigenesis.

Cordycepin inhibits the proliferation of malignant peripheral nerve sheath tumor cells through the p53/Sp1/tubulin pathway.

Neurofibromatosis type 1 (NF1) is one of the most common hereditary neurocutaneous disorders. In addition to skin pigmentation and cutaneous neurofibroma, some patients developed the plexiform neurofibroma since birth. Plexiform neurofibroma has abundant Schwann cells, fibroblasts, mast cells, blood vessels, and connective tissues, which increases the risk of developing a malignant peripheral nerve sheath tumor (MPNST). MPNST is a highly invasive cancer with no effective therapeutic agent. Cordycepin or 3'-deoxyadenosine is an extract from cordyceps militaris, which has been reported as an anti-inflammation and anti-tumor agent. Herein, we evaluated cordycepin's anti-proliferative effect on MPNST cell lines both in vitro and in vivo. Cordycepin inhibited the MPNST cell growth with an arrest of cell cycle at G2/M and S phases. The administration of naringin and pentostatin, inhibitors for adenosine deaminase (ADA), enzyme responsible for cordycepin degradation, did not show a synergistic effect in MPNST cells treated with cordycepin. However, the combined treatment enhanced the decrease of tumors in xenograft mouse model. Immunoblotting showed a decreased level of p53 protein in all MPNST cell lines, but S462TY cells. After cordycepin treatment, the levels of ERK, survivin, pAKT, and Sp1 proteins also decreased. The level of tubulin, but not actin or GAPDH, decreased in a dose-dependent manner. The microtubule network which is composed of tubulins was markedly decomposed in those treated MPNST cells. To elucidate the epigenetic control of transcription, ChIP-qPCR assay of the Sp1 and tubulin promoter regions revealed decreased Sp1 binding. The incorporation of 3'-doexyadenosine is detrimental for the process of poly(A) tail elongation. The poly(A) tail length assay showed the tail length in Sp1 and tubulin transcripts decreased in the treated cells. Nevertheless, the administration of SP1 protein to the treated cells could not rescue them completely. Furthermore, the p53-knocked-down cells (S462TY) where the expression of both p53 and Sp1 was suppressed, were vulnerable to cordycepin. The p53 protein could ameliorate the effect. In summary, cordycepin is effective to inhibit the growth of MPNST, probably through the pathway of p53/Sp1/tubulin.

Changes in Resurgent Sodium Current Contribute to the Hyperexcitability of Muscles in Patients with Paramyotonia Congenita.

Paramyotonia congenita (PMC) is a rare hereditary skeletal muscle disorder. The major symptom, muscle stiffness, is frequently induced by cold exposure and repetitive exercise. Mutations in human SCN4A gene, which encodes the α-subunit of Nav1.4 channel, are responsible for PMC. Mutation screening of SCN4A gene from two PMC families identified two missense mutations, p.T1313M and p.R1448H. To elucidate the electrophysiological abnormalities caused by the mutations, the p.T1313M, p.R1448H, and wild-type (WT) SCN4A genes were transient expressed on Chinese hamster ovary (CHO-K1) cells. The detailed study on the gating defects of the mutant channels using the whole-cell patch clamping technique was performed. The mutant Nav1.4 channels impaired the basic gating properties with increasing sustained and window currents during membrane depolarization and facilitated the genesis of resurgent currents during repolarization. The mutations caused a hyperpolarization shift in the fast inactivation and slightly enhanced the slow inactivation with an increase in half-maximal inactivation voltage. No differences were found in the decay kinetics of the tail current between mutant and WT channels. In addition to generating the larger resurgent sodium current, the time to peak in the mutant channels was longer than that in the WT channels. In conclusion, our results demonstrated that the mutations p.T1313M and p.R1448H in Nav1.4 channels can enhance fast inactivation, slow inactivation, and resurgent current, revealing that subtle changes in gating processes can influence the clinical phenotype.