Presynaptic nerve terminals are highly specialized vesicle-trafficking machines. Neurotransmitter release from these terminals is sustained by constant local recycling of synaptic vesicles ...independent from the neuronal cell body. This independence places significant constraints on maintenance of synaptic protein complexes and scaffolds. Key events during the synaptic vesicle cycle-such as exocytosis and endocytosis-require formation and disassembly of protein complexes. This extremely dynamic environment poses unique challenges for proteostasis at synaptic terminals. Therefore, it is not surprising that subtle alterations in synaptic vesicle cycle-associated proteins directly or indirectly contribute to pathophysiology seen in several neurologic and psychiatric diseases. In contrast to the increasing number of examples in which presynaptic dysfunction causes neurologic symptoms or cognitive deficits associated with multiple brain disorders, synaptic vesicle-recycling machinery remains an underexplored drug target. In addition, irrespective of the involvement of presynaptic function in the disease process, presynaptic machinery may also prove to be a viable therapeutic target because subtle alterations in the neurotransmitter release may counter disease mechanisms, correct, or compensate for synaptic communication deficits without the need to interfere with postsynaptic receptor signaling. In this article, we will overview critical properties of presynaptic release machinery to help elucidate novel presynaptic avenues for the development of therapeutic strategies against neurologic and neuropsychiatric disorders.
ALS (Amyotrophic Lateral Sclerosis) is a neurodegenerative disease characterized by the redistribution of the RNA binding protein TDP-43 in affected neurons: from predominantly nuclear to aggregated ...in the cytosol. However, the determinants of TDP-43 localization and the cellular insults that promote redistribution are incompletely understood. Here, we show that the putative Nuclear Export Signal (NES) is not required for nuclear egress of TDP-43. Moreover, when the TDP-43 domain which contains the putative NES is fused to a reporter protein, YFP, the presence of the NES is not sufficient to mediate nuclear exclusion of the fusion protein. We find that the previously studied "∆NES" mutant, in which conserved hydrophobic residues are mutated to alanines, disrupts both solubility and splicing function. We further show that nuclear export of TDP-43 is independent of the exportin XPO1. Finally, we provide evidence that nuclear egress of TDP-43 is size dependent; nuclear export of dTomato TDP-43 is significantly impaired compared to Flag TDP-43. Together, these results suggest nuclear export of TDP-43 is predominantly driven by passive diffusion.
Synaptic vesicle recycling is essential for maintaining normal synaptic function. The coupling of exocytosis and endocytosis is assumed to be Ca2+ dependent, but the exact role of Ca2+ and its key ...effector synaptotagmin-1 (syt1) in regulation of endocytosis is poorly understood. Here, we probed the role of syt1 in single- as well as multi-vesicle endocytic events using high-resolution optical recordings. Our experiments showed that the slowed endocytosis phenotype previously reported after syt1 loss of function can also be triggered by other manipulations that promote asynchronous release such as Sr2+ substitution and complexin loss of function. The link between asynchronous release and slowed endocytosis was due to selective targeting of fused synaptic vesicles toward slow retrieval by the asynchronous release Ca2+ sensor synaptotagmin-7. In contrast, after single synaptic vesicle fusion, syt1 acted as an essential determinant of synaptic vesicle endocytosis time course by delaying the kinetics of vesicle retrieval in response to increasing Ca2+ levels.
•Loss of syt1, complexins, or Sr2+ substitution slows endocytosis after activity•Asynchronously released synaptic vesicles are retrieved via slow endocytosis•Link between asynchronous release and slowed endocytosis requires synaptotagmin-7•Whereas, after synchronous single synaptic vesicle fusion, syt1 delays endocytosis
In this study, Li and colleagues demonstrate that synaptic vesicle fusion machinery, comprised of synaptotagmin-1, complexins, and synaptotagmin-7, in addition to determining the timing and Ca2+ dependence of neurotransmitter release, also dictates the properties of subsequent synaptic vesicle endocytosis.
The deadliest anaplastic thyroid cancer (ATC) often transforms from indolent differentiated thyroid cancer (DTC); however, the complex intratumor transformation process is poorly understood. We ...investigated an anaplastic transformation model by dissecting both cell lineage and cell fate transitions using single-cell transcriptomic and genetic alteration data from patients with different subtypes of thyroid cancer. The resulting spectrum of ATC transformation included stress-responsive DTC cells, inflammatory ATC cells (iATCs), and mitotic-defective ATC cells and extended all the way to mesenchymal ATC cells (mATCs). Furthermore, our analysis identified 2 important milestones: (a) a diploid stage, in which iATC cells were diploids with inflammatory phenotypes and (b) an aneuploid stage, in which mATCs gained aneuploid genomes and mesenchymal phenotypes, producing excessive amounts of collagen and collagen-interacting receptors. In parallel, cancer-associated fibroblasts showed strong interactions among mesenchymal cell types, macrophages shifted from M1 to M2 states, and T cells reprogrammed from cytotoxic to exhausted states, highlighting new therapeutic opportunities for the treatment of ATC.
Aim
This study aims to assess the potential effects of zanubrutinib on the activity of cytochrome P450 (CYP) enzymes and drug transporter proteins using a cocktail probe approach.
Methods
Patients ...received single oral doses of probe drugs alone and after at least 8 days of treatment with zanubrutinib 160 mg twice daily in a single‐sequence study in 18 healthy male volunteers. Simultaneous doses of 10 mg warfarin (CYP2C9) and 2 mg midazolam (CYP3A) were administered on Day 1 and Day 14, 0.25 mg digoxin (P‐glycoprotein P‐gp) and 10 mg rosuvastatin (breast cancer resistance protein BCRP) on Day 3 and Day 16, and 20 mg omeprazole (CYP2C19) on Day 5 and Day 18. Pharmacokinetic (PK) parameters were estimated from samples obtained up to 12 h post dose for zanubrutinib; 24 h for digoxin, omeprazole and midazolam; 48 h for rosuvastatin; and 144 h for warfarin.
Results
The ratios (%) of geometric least squares means (90% confidence intervals) for the area under the concentration–time curve from time zero to the last quantifiable concentration in the presence/absence of zanubrutinib were 99.80% (97.41–102.2%) for S‐warfarin; 52.52% (48.49–56.88%) for midazolam; 111.3% (103.8–119.3%) for digoxin; 89.45% (78.73–101.6%) for rosuvastatin; and 63.52% (57.40–70.30%) for omeprazole. Similar effects were observed for maximum plasma concentrations.
Conclusions
Zanubrutinib 320 mg total daily dose had minimal or no effect on the activity of CYP2C9, BCRP and P‐gp, but decreased the systemic exposure of CYP3A and CYP2C19 substrates (mean reduction <50%).
Recent studies suggest that spontaneous and action potential-evoked neurotransmitter release processes are independently regulated. However, the mechanisms that uncouple the two forms of ...neurotransmission remain unclear. In cultured mouse and rat neurons, we show that the two C2 domain-containing protein copine-6 is localized to presynaptic terminals and binds to synaptobrevin2 as well as other SNARE proteins in a Ca
-dependent manner. Ca
-dependent interaction of copine-6 with synaptobrevin2 selectively suppresses spontaneous neurotransmission in a reaction that requires the tandem tryptophan residues at the C-terminal region of synaptobrevin2. Accordingly, copine-6 loss of function augmented presynaptic Ca
elevation-mediated neurotransmitter release. Intracellular Ca
chelation, on the other hand, occluded copine-6-mediated suppression of release. We also evaluated the molecular specificity of the copine-6-dependent regulation of spontaneous release and found that overexpression of copine-6 did not suppress spontaneous release in synaptobrevin2-deficient neurons. Together, these results suggest that copine-6 acts as a specific Ca
-dependent suppressor of spontaneous neurotransmission.
Synaptic transmission occurs both in response to presynaptic action potentials and spontaneously, in the absence of stimulation. Currently, much more is understood about the mechanisms underlying action potential-evoked neurotransmission compared with spontaneous release. However, recent studies have shown selective modulation of spontaneous neurotransmission process by several neuromodulators, suggesting specific molecular regulation of spontaneous release. In this study, we identify copine-6 as a specific regulator of spontaneous neurotransmission. By both gain-of-function and loss-of-function experiments, we show that copine-6 functions as a Ca
-dependent suppressor of spontaneous release. These results further elucidate the mechanisms underlying differential regulation of evoked and spontaneous neurotransmitter release.
Coupling between voltage-gated Ca2+ influx and synaptic vesicle exocytosis is essential for rapid evoked neurotransmission. Acuna et al. show that the knockout of RIM-BPs, which are key structural ...components of this coupling, decreases the reliability of evoked neurotransmitter release.
Coupling between voltage-gated Ca2+ influx and synaptic vesicle exocytosis is essential for rapid evoked neurotransmission. Acuna et al. show that the knockout of RIM-BPs, which are key structural components of this coupling, decreases the reliability of evoked neurotransmitter release.
The evolution of infectious diseases (IDs) poses a challenge to many ID physicians, who must either adapt or transition to another career track. This national cross-sectional study assessed the ...current working conditions and problems faced by ID professionals in China.
A national questionnaire survey of ID physicians and their facilities throughout China was performed in May–June 2016 using stratified random sampling.
A total of 156/300 (52.0%) ID departments and 1071/2250 (47.6%) physicians from 21 provinces participated in the survey. Overall, 151 (96.2%) of 156 hospitals had ID wards and 141 (90.4%) provided outpatient consultations. The average number of ID physicians per department was 10.32 ± 6.57. The ratio of patient beds to doctors was 5: 1, and the ratio of patient beds to nurses was 5: 1.85. Training in IDs was available in 126 (80.8%), and ID research was performed in 108 (69.2%), of the 156 departments. The main service provided by ID physicians was the management of legally notifiable communicable diseases. The annual income of 942 (88.0%) of the 1071 physicians was below $15 000. Of these physicians, 870 (81.2%) felt high or very high pressure in their work, whereas only 514 (48.0%) were satisfied or very satisfied with their jobs.
The limited medical service provided by ID physicians is poorly aligned with current healthcare demands. Moreover, the heavy workloads, high stress, poor compensation and limited career prospects for ID physicians in China impede the continued development of specialists and places them in a career dilemma. ID physicians should work to develop and diversify the field and to enhance their capacities by learning new technologies and collaborating with other medical disciplines.
To understand the types of gene action controlling seven quantitative traits in rice, we carried out quantitative trait locus (QTL) mapping in order to distinguish between the main-effect QTLs ...(M-QTLs) and digenic epistatic QTLs (E-QTLs) responsible for the trait performance of 254 recombinant inbred lines (RILs) from rice varieties Lemont/Teqing and two backcross hybrid (BCF1) populations derived from these RILs. We identified 44 M-QTL and 95 E-QTL pairs in the RI and BCF1 populations as having significant effects on the mean values and mid-parental heterosis of heading date, plant height, flag leaf length, flag leaf width, panicle length, spikelet number and spikelet fertility. The E-QTLs detected collectively explained a larger portion of the total phenotypic variation than the M-QTLs in both the RI and BCF1 populations. In both BCF1 populations, over-dominant (or under-dominant) loci were more important than additive and complete or partially dominant loci for M-QTLs and E-QTL pairs, thereby supporting prior findings that overdominance resulting from epistatic loci are the primary genetic basis of inbreeding depression and heterosis in rice.
Background
We aimed to develop a nomogram model of overall survival (OS) and cancer-specific survival (CSS) in patients with differentiated thyroid cancer with distant metastases, and to evaluate and ...validate the nomogram. Also, its prognostic value was compared with that of the 8th edition of the American Joint Committee on Cancer tumor–node–metastasis staging system (AJCC8SS).
Methods
Patients with distant metastatic differentiated thyroid cancer (DMDTC) from 2004 to 2015 were selected from the Surveillance, Epidemiology, and End Results (SEER) Program to extract the clinical variables used for analysis. A total of 906 patients were divided into a training set (
n
= 634) and validation set (
n
= 272). OS and CSS were selected as the primary end point and secondary end point. LASSO regression analysis and multivariate Cox regression analysis were applied to screen variables for constructing OS and CSS nomograms for survival probability at 3, 5, and 10 years. Nomograms were evaluated and validated using the consistency index (C-index), time-dependent receiver operator characteristic (ROC) curves, area under the ROC curve, calibration curves, and decision curve analysis (DCA). The predictive survival of the nomogram was compared with that of AJCC8SS. Kaplan–Meier curves and log-rank tests were used to evaluate the risk-stratification ability OS and CSS nomograms.
Results
CS and CSS nomograms included six independent predictors: age, marital status, type of surgical procedure, lymphadenectomy, radiotherapy, and T stage. The C-index for the OS nomogram was 0.7474 (95% CI = 0.7199–0.775), and that for the CSS nomogram was 0.7572 (0.7281–0.7862). The nomogram showed good agreement with the “ideal” calibration curve in the training set and validation sets. DCA confirmed that the survival probability predicted by the nomogram had high clinical predictive value. The nomogram could stratify patients more accurately, and showed more robust accuracy and predictive power, than AJCC8SS.
Conclusions
We established and validated prognostic nomograms for patients with DMDTC, which had significant clinical value compared with AJCC8SS.
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