CRISPR-based identification of N-terminal acetylation in synucleinopathies.

A recent study by Kumar et al. identified several biological pathways that regulate the levels of endogenous alpha-synuclein (α-synuclein). They specifically highlighted the N-terminal acetylation (NTA) pathway as an important factor in maintaining the stability of endogenous α-synuclein, suggesting targeting the NTA pathway as a potential therapeutic approach.

Targeted degradation of SNCA/α-synuclein aggregates in neurodegeneration using the AUTOTAC chemical platform.

Parkinson disease (PD) characterized by dopaminergic neuronal loss is caused by aggregation of misfolded SNCA/α-synuclein. We recently developed autophagy-targeting chimera (AUTOTAC), a targeted protein degradation (TPD) technology based on the macroautophagy/autophagy-lysosome pathway (ALP). In this study, we employed AUTOTAC to synthesize ATC161, a chimeric compound that adopts Anle138b as target-binding ligand (TBL) for SNCA aggregates. The autophagy-targeting ligand (ATL) of ATC161 was designed to allosterically activate the autophagy receptor SQSTSM1/p62 (sequestosome 1), a key step for targeting SNCA aggregates to the phagophore. The lysosomal degradation of SNCA aggregates by ATC161 acutely occurs at DC50 of 100-500 nM with no significant off-target degradation of monomeric SNCA. ATC161 protects cells from DNA and mitochondrial damage by SNCA aggregates. In PD model mice, oral administration of ATC161 decreases the level of SNCA aggregates and their propagation across brain regions, which mitigates glial inflammatory responses and improves muscle strength and locomotive activity. An Investigational New Drug (IND) was approved by the Korean Food and Drug Administration for a phase 1 clinical trial to treat PD, Alzheimer disease (AD), progressive supranuclear palsy (PSP), and amyotrophic lateral sclerosis (ALS). We suggest that AUTOTAC provides a platform for drug discovery in proteinopathies and other diseases.

Changes in oligodendroglial subpopulations in Parkinson's disease.

Parkinson's disease (PD) is characterized by a selective loss of dopaminergic neurons. While most research on PD conducted to date has focused on neurons and, to a certain extent, glia, few studies have investigated changes in oligodendroglia. Here, we investigated the heterogeneity of oligodendrocytes from PD patients compared with those of control cases by analyzing single-nuclei transcriptomes. These analyses revealed the presence of distinct oligodendrocyte populations in PD patients indicative of corresponding variations in molecular features, notably including activation of inflammatory responses, response to protein folding stress, and myelination abnormalities. We confirmed myelination abnormalities in an α-synuclein preformed fibril-injection mouse model of PD. These results suggest that oligodendrocytes acquire disease-associated phenotypes in PD and may contribute to the accompanying neurodegeneration.

Targeted degradation of ⍺-synuclein aggregates in Parkinson's disease using the AUTOTAC technology.

BACKGROUND: There are currently no disease-modifying therapeutics for Parkinson's disease (PD). Although extensive efforts were undertaken to develop therapeutic approaches to delay the symptoms of PD, untreated α-synuclein (α-syn) aggregates cause cellular toxicity and stimulate further disease progression. PROTAC (Proteolysis-Targeting Chimera) has drawn attention as a therapeutic modality to target α-syn. However, no PROTACs have yet shown to selectively degrade α-syn aggregates mainly owing to the limited capacity of the proteasome to degrade aggregates, necessitating the development of novel approaches to fundamentally eliminate α-syn aggregates. METHODS: We employed AUTOTAC (Autophagy-Targeting Chimera), a macroautophagy-based targeted protein degradation (TPD) platform developed in our earlier studies. A series of AUTOTAC chemicals was synthesized as chimeras that bind both α-syn aggregates and p62/SQSTM1/Sequestosome-1, an autophagic receptor. The efficacy of Autotacs was evaluated to target α-syn aggregates to phagophores and subsequently lysosomes for hydrolysis via p62-dependent macroautophagy. The target engagement was monitored by oligomerization and localization of p62 and autophagic markers. The therapeutic efficacy to rescue PD symptoms was characterized in cultured cells and mice. The PK/PD (pharmacokinetics/pharmacodynamics) profiles were investigated to develop an oral drug for PD. RESULTS: ATC161 induced selective degradation of α-syn aggregates at DC50 of ~ 100 nM. No apparent degradation was observed with monomeric α-syn. ATC161 mediated the targeting of α-syn aggregates to p62 by binding the ZZ domain and accelerating p62 self-polymerization. These p62-cargo complexes were delivered to autophagic membranes for lysosomal degradation. In PD cellular models, ATC161 exhibited therapeutic efficacy to reduce cell-to-cell transmission of α-syn and to rescue cells from the damages in DNA and mitochondria. In PD mice established by injecting α-syn preformed fibrils (PFFs) into brain striata via stereotaxic surgery, oral administration of ATC161 at 10 mg/kg induced the degradation of α-syn aggregates and reduced their propagation. ATC161 also mitigated the associated glial inflammatory response and improved muscle strength and locomotive activity. CONCLUSION: AUTOTAC provides a platform to develop drugs for PD. ATC161, an oral drug with excellent PK/PD profiles, induces selective degradation of α-syn aggregates in vitro and in vivo. We suggest that ATC161 is a disease-modifying drug that degrades the pathogenic cause of PD.

Estimating the Total Societal Cost of a Hexavalent Vaccine versus a Pentavalent Vaccine with Hepatitis B in South Korea.

In South Korea, the ready-to-use hexavalent vaccine (against diphtheria, tetanus, pertussis, poliovirus, Haemophilus influenzae type b, and hepatitis B) is not listed despite its facility of no need to reconstitute. It, therefore, has the potential to augment the efficiency of prevention against the six infectious diseases, and it may reduce vaccine-related errors of reconstitution when compared with the currently used vaccination scheme of the pentavalent vaccine with the additional shots against hepatitis B. Given the assumed clinical equivalence between the two vaccination schemes, a cost-minimization analysis has been performed from a societal perspective including all the medical and non-medical direct and indirect costs when vaccinating one birth cohort. The results indicate that the ready-to-use hexavalent vaccine induces a cost reduction of KRW 47,155 (USD36.22) per infant or 12,026 million Korean Won ($9,236,417) in total for the whole birth cohort with 260,500 children. Using the ready-to-use hexavalent vaccine causes a lower infection rate, has fewer vaccination sessions, and may save much time as compared with the current vaccination scheme in place. The ready-to-use hexavalent vaccine may, therefore, benefit the National Immunization Program by reducing the total societal costs of vaccination while improving convenience of infants, parents, and medical care professionals.

Inflammation promotes synucleinopathy propagation.

The clinical progression of neurodegenerative diseases correlates with the spread of proteinopathy in the brain. The current understanding of the mechanism of proteinopathy spread is far from complete. Here, we propose that inflammation is fundamental to proteinopathy spread. A sequence variant of α-synuclein (V40G) was much less capable of fibril formation than wild-type α-synuclein (WT-syn) and, when mixed with WT-syn, interfered with its fibrillation. However, when V40G was injected intracerebrally into mice, it induced aggregate spreading even more effectively than WT-syn. Aggregate spreading was preceded by sustained microgliosis and inflammatory responses, which were more robust with V40G than with WT-syn. Oral administration of an anti-inflammatory agent suppressed aggregate spreading, inflammation, and behavioral deficits in mice. Furthermore, exposure of cells to inflammatory cytokines increased the cell-to-cell propagation of α-synuclein. These results suggest that the inflammatory microenvironment is the major driver of the spread of synucleinopathy in the brain.

TNF-α promotes α-synuclein propagation through stimulation of senescence-associated lysosomal exocytosis.

Cell-to-cell propagation of α-synuclein is thought to be the underlying mechanism of Parkinson's disease progression. Recent evidence suggests that inflammation plays an important role in the propagation of protein aggregates. However, the mechanism by which inflammation regulates the propagation of aggregates remains unknown. Here, using in vitro cultures, we found that soluble factors secreted from activated microglia promote cell-to-cell propagation of α-synuclein and further showed that among these soluble factors, TNF-α had the most robust stimulatory activity. Treatment of neurons with TNF-α triggered cellular senescence, as shown by transcriptomic analyses demonstrating induction of senescence-associated genes and immunoanalysis of senescence phenotype marker proteins. Interestingly, secretion of α-synuclein was increased in senescent neurons, reflecting acquisition of a senescence-associated secretory phenotype (SASP). Using vacuolin-1, an inhibitor of lysosomal exocytosis, and RNAi against rab27a, we demonstrated that the SASP was mediated by lysosomal exocytosis. Correlative light and electron microscopy and immunoelectron microscopy confirmed that propagating α-synuclein aggregates were present in electron-dense lysosome-like compartments. TNF-α promoted the SASP through stimulation of lysosomal exocytosis, thereby increasing the secretion of α-synuclein. Collectively, these results suggest that TNF-α is the major inflammatory factor that drives cell-to-cell propagation of α-synuclein by promoting the SASP and subsequent secretion of α-synuclein.

Highly Flexible and Durable Thermoelectric Power Generator Using CNT/PDMS Foam by Rapid Solvent Evaporation.

Using a simple, rapid solvent evaporation process, the authors produced 3D carbon nanotube (CNT)/polydimethylsiloxane (PDMS) foams with both high thermoelectric (TE) and good mechanical performance and used them to fabricate highly flexible and durable TE generators. The numerous pores and interfaces in the CNT/PDMS foams, which have porosities exceeding 87%, afford very low thermal conductivity of 0.13 W m-1 K-1 . The foam has a zT value of 6.6 × 10-3 , which is twice as high as that of pristine CNT foam. Importantly, the CNT/PDMS foam exhibits good tensile strength of 0.78 MPa, elongation greater than 20%, and excellent resilience even at compressive strain of 80%. This foam is used to fabricate a highly flexible TE foam generator that exhibits a moderate output power of 1.9 µW generated from the large temperature gradient of 18.1 K produced by applied heat. The authors also demonstrate a practical TE foam generator that produces sustainable output power of 3.1 µW under a compressive strain of 80% and 38.2 nW under the continuous vibrational stress produced by a car engine. The TE foam generator also exhibits excellent stability and durability under cyclic bending and harsh vibrational stress.

Neurodevelopmental defects and neurodegenerative phenotypes in human brain organoids carrying Parkinson's disease-linked DNAJC6 mutations.

Loss-of-function mutations of DNAJC6, encoding HSP40 auxilin, have recently been identified in patients with early-onset Parkinson's disease (PD). To study the roles of DNAJC6 in PD pathogenesis, we used human embryonic stem cells with CRISPR-Cas9-mediated gene editing. Here, we show that DNAJC6 mutations cause key PD pathologic features, i.e., midbrain-type dopamine (mDA) neuron degeneration, pathologic α-synuclein aggregation, increase of intrinsic neuronal firing frequency, and mitochondrial and lysosomal dysfunctions in human midbrain-like organoids (hMLOs). In addition, neurodevelopmental defects were also manifested in hMLOs carrying the mutations. Transcriptomic analyses followed by experimental validation revealed that defects in DNAJC6-mediated endocytosis impair the WNT-LMX1A signal during the mDA neuron development. Furthermore, reduced LMX1A expression during development caused the generation of vulnerable mDA neurons with the pathologic manifestations. These results suggest that the human model of DNAJC6-PD recapitulates disease phenotypes and reveals mechanisms underlying disease pathology, providing a platform for assessing therapeutic interventions.

Nephrologists' Perspectives on Decision Making About Life-Sustaining Treatment and Palliative Care at End of Life: A Questionnaire Survey in Korea.

Background: Nephrologists commonly engage in decision making regarding the withholding or withdrawal of dialysis and palliative care in patients at end of life (EoL). However, these issues remain an unsolved dilemma for nephrologists. Objective: To explore nephrologists' perceptions on the decision-making process about withholding or withdrawing dialysis and palliative care in Korea. Design: A nationwide 25-item questionnaire online survey via e-mail. Setting/Subjects: A total of 369 Korean nephrologists completed the survey. Results: The proportions of respondents who stated that withholding or withdrawing dialysis at EoL is ethically appropriate were 87.3% and 86.2%, respectively. A total of 72.4% respondents thought that withdrawal of dialysis in a maintenance dialysis patient is ethically appropriate. Responses regarding patient features that should be considered to withhold or withdraw dialysis were as follows: dialysis intolerance (84.3%), poor performance status (74.8%), patient's active request (47.2%), age (28.7%), very severe dementia (27.1%), and several comorbidities (16.5%). Among those nephrologists who responded to the question about the minimum age, at which dialysis should be withheld or withdrawn, most specified an age between 80 and 90 years (94.3%). Fifty-eight percent of respondents stated that terminally ill dialysis patients should be allowed to use palliative care facilities. In addition, a number of nephrologists thought that adequate palliative care facilities, specific treatment guidelines, enough time to manage patients, financial support, and adequate medical experts are necessary. Conclusions: Korean nephrologists thought that withholding or withdrawing dialysis at EoL is ethically appropriate, even in maintenance dialysis patients. Therefore, consensus guidelines for palliative care after withholding or withdrawal of dialysis are needed.

The LRRK2-RAB axis in regulation of vesicle trafficking and α-synuclein propagation.

LRRK2 and SNCA, the gene for α-synuclein, are the two of the most important genetic factors of Parkinson's disease (PD). A-synuclein is aggregated and accumulated in neurons and glia in PD and considered the pathogenic culprit of the disease. A-synuclein aggregates spread from a few discrete regions of the brain to larger areas as the disease progresses through cell-to-cell propagation mechanism. LRRK2 is involved in the regulation of vesicle trafficking, in particular in the endolysosomal and autophagic pathways. Studies also suggest that LRRK2 might regulate the pathogenic actions of α-synuclein. However, the relationship between these two proteins in the pathogenesis of PD remains elusive. Here, we review the current literature on the pathophysiological function of LRRK2 with an emphasis on its role in the endolysosomal and autophagic pathways. We also propose a potential mechanism by which LRRK2 is involved in the regulation of aggregation and the propagation of α-synuclein.

Oxidative stress in vagal neurons promotes parkinsonian pathology and intercellular α-synuclein transfer.

Specific neuronal populations display high vulnerability to pathological processes in Parkinson's disease (PD). The dorsal motor nucleus of the vagus nerve (DMnX) is a primary site of pathological α-synuclein deposition and may play a key role in the spreading of α-synuclein lesions within and outside the CNS. Using in vivo models, we show that cholinergic neurons forming this nucleus are particularly susceptible to oxidative challenges and accumulation of reactive oxidative species (ROS). Targeted α-synuclein overexpression within these neurons triggered an oxidative stress that became significantly more pronounced after exposure to the ROS-generating agent paraquat. A more severe oxidative stress resulted in enhanced production of oxidatively modified forms of α-synuclein, increased α-synuclein aggregation into oligomeric species and marked degeneration of DMnX neurons. Enhanced oxidative stress also affected neuron-to-neuron protein transfer, causing an increased spreading of α-synuclein from the DMnX toward more rostral brain regions. In vitro experiments confirmed a greater propensity of α-synuclein to pass from cell to cell under pro-oxidant conditions, and identified nitrated α-synuclein forms as highly transferable protein species. These findings substantiate the relevance of oxidative injury in PD pathogenetic processes, establish a relationship between oxidative stress and vulnerability to α-synuclein pathology and define a new mechanism, enhanced cell-to-cell α-synuclein transmission, by which oxidative stress could promote PD development and progression.

Estimation of Health Utilities Based on the Response to Treatment in Atopic Dermatitis: a Population-based Study.

PURPOSE: This study estimated utility weights based on the response to treatment for atopic dermatitis in the general population. METHODS: The Korean general population aged 20-60 years was stratified by using a random sampling method based on age and sex. Two hypothetical health states of atopic dermatitis were developed: response to treatment and no response to treatment. Health utility values were estimated by using time trade-off (TTO) based on a period of 10 years, TTO based on life expectancy, and EuroQol 5-Dimension (EQ-5D) including a visual analog scale (VAS). The mean utility value and 95% CI were derived, and comparisons of subgroups using the t test and ANOVA were performed. We conducted a multilevel analysis after controlling the sociodemographic variables to consider repeated measures. FINDINGS: A total of 155 participants were included in the survey. Their mean age was 39.7 years; 58.7% of participants were women. The mean health utility values for response and no response using TTO based on 10 years were 0.847 and 0.380, respectively. The estimated health utility values of response and no response were 0.865 and 0.476 using TTO based on life expectancy, and 0.814 and 0.279 using EQ-5D. For VAS, the response and no response were 0.744 and 0.322. After controlling the covariates, the important factors that affected utility values were response and no response to treatment (P < 0.001). IMPLICATIONS: This study showed that the utility weights of people with no response to atopic dermatitis treatment were lower compared with response from the general population. Health care providers should therefore consider symptom control as an important factor affecting the quality of life of those with atopic dermatitis.

LRRK2 kinase regulates α-synuclein propagation via RAB35 phosphorylation.

Propagation of α-synuclein aggregates has been suggested as a contributing factor in Parkinson's disease (PD) progression. However, the molecular mechanisms underlying α-synuclein aggregation are not fully understood. Here, we demonstrate in cell culture, nematode, and rodent models of PD that leucine-rich repeat kinase 2 (LRRK2), a PD-linked kinase, modulates α-synuclein propagation in a kinase activity-dependent manner. The PD-linked G2019S mutation in LRRK2, which increases kinase activity, enhances propagation efficiency. Furthermore, we show that the role of LRRK2 in α-synuclein propagation is mediated by RAB35 phosphorylation. Constitutive activation of RAB35 overrides the reduced α-synuclein propagation phenotype in lrk-1 mutant C. elegans. Finally, in a mouse model of synucleinopathy, administration of an LRRK2 kinase inhibitor reduced α-synuclein aggregation via enhanced interaction of α-synuclein with the lysosomal degradation pathway. These results suggest that LRRK2-mediated RAB35 phosphorylation is a potential therapeutic target for modifying disease progression.

Amplification of distinct α-synuclein fibril conformers through protein misfolding cyclic amplification.

Amyloid fibril formation has been implicated in the pathogenesis of neurodegenerative diseases. Fibrillation generates numerous conformers. Presumably, the conformers may possess specific biological properties, thus providing a biochemical framework for strains of prions. However, the precise relationship between various fibril conformers and their pathogenic functions has not been determined because of limited accessibility to adequate amounts of fibrils from tissue samples. α-Synuclein is one such protein, and it has been implicated in Parkinson disease. Using a technique known as protein misfolding cyclic amplification, originally developed for amplifying prions, we established a procedure through which the amplification of α-synuclein fibrils is possible. With a trace amount of seeds, we succeeded in amplifying α-synuclein fibrils. The replication of the seeds was faithful in terms of conformation even after multiple rounds of cyclic amplification. Moreover, two transgenic mouse strains each representing a distinct synucleinopathy were used to investigate different conformers by using this technique. The amplified α-synuclein fibrils derived from the tissue extracts of these two strains led to the production of two different fibril conformers with distinct proteinase K digestion profiles. Together, our results demonstrated that a trace amount of α-synuclein fibrils in tissue extracts could be amplified with their conformations conserved. This procedure should be useful in amplifying α-synuclein fibrils from the brains and body fluids of patients afflicted with synucleinopathies and may serve as a potential diagnostic tool for Parkinson disease and other synucleinopathies.

Relationships among Obesity, Sarcopenia, and Osteoarthritis in the Elderly.

BACKGROUND: The present study examined the correlations between obesity, sarcopenia, and osteoarthritis in Korea's elderly population. METHODS: A cross-sectional analysis of 1,865 and 1,769 respondents with knee osteoarthritis and lumbar spondylosis, respectively, was performed by using data from the 2010 and 2011 Korea National Health and Nutrition Examination Survey. Obesity was defined as a body mass index of ≥25 kg/m2; osteoarthritis, as a Kellgren/Lawrence grade of ≥2; and sarcopenia, as an appendicular skeletal muscle mass (ASM; ASM/weight ×100) on dual-energy X-ray absorptiometry of two standard deviations below the mean reference value. RESULTS: The unadjusted and age-adjusted risks of knee osteoarthritis were as follows: 1.88 and 1.92 times greater, respectively, for male subjects with sarcopenic obesity; 6.03 and 7.64 times greater, respectively, for female subjects with non-sarcopenic obesity; and 1.97 and 2.43 times greater, respectively, for female subjects with sarcopenic obesity. The age-and-waist circumference-adjusted risks were 5.88 and 1.80 times greater for the female subjects with non-sarcopenic and sarcopenic obesities, respectively. No statistically significant finding was obtained for lumbar spondylosis. CONCLUSION: Obesity and sarcopenia were associated with knee osteoarthritis in the elderly subjects. The risk of knee osteoarthritis was greater in the male subjects with sarcopenic obesity than in the male subjects with non-sarcopenic obesity. In the female subjects, the risk of knee osteoarthritis was high in both obesity groups. Further research to explain the sex-related difference in knee osteoarthritis risk based on body composition will be beneficial.

Rhabdomyolysis associated with single-dose intravenous esomeprazole administration: A case report.

BACKGROUND: Proton pump inhibitors are usually safe, although serious adverse effects can occur. We report the first case of rhabdomyolysis associated with single-dose intravenous esomeprozole administration. METHODS: A 45-year-old Korean male visited our emergency room because of persistent lower chest discomfort that started 10 hours before. He had been diagnosed with diabetes and coronary heart disease, but discontinued oral hypoglycemic agents 1 month earlier. He continued to take medications for coronary heart disease. There was no abnormality on an electrocardiogram or in cardiac enzymes. Initial laboratory findings did not show abnormalities for muscle enzymes. Esomeprozole 40 mg was administrated intravenously for the control of his ambiguous chest discomfort. Then, 12 hours later, he complained of abrupt severe right buttock pain. An area of tender muscle swelling 8 cm in diameter was seen on his right buttock area. Creatine kinase and lactate dehydrogenase were elevated to 40,538 and 1326 U/L, respectively. A bone scan using 20 mCi of Tc-hydroxymethylene diphosphonate was compatible with rhabdomyolysis. RESULTS: His muscular symptoms, signs, and laboratory findings improved markedly with conservative management, including hydration and urine alkalinization. He is being followed in the outpatient department with no evidence of recurrence. CONCLUSION: We should keep in mind that single-dose intravenous administration of esomeprazole can induce rhabdomyolysis.