Tau Accumulation via Reduced Autophagy Mediates GGGGCC Repeat Expansion-Induced Neurodegeneration in Drosophila Model of ALS

Expansions of trinucleotide or hexanucleotide repeats lead to several neurodegenerative disorders, including Huntington disease [caused by expanded CAG repeats (CAGr) in the HTT gene], and amyotrophic lateral sclerosis [ALS, possibly caused by expanded GGGGCC repeats (G4C2r) in the C9ORF72 gene], of which the molecular mechanisms remain unclear. Here, we demonstrated that lowering the Drosophila homologue of tau protein (dtau) significantly rescued in vivo neurodegeneration, motor performance impairments, and the shortened life-span in Drosophila expressing expanded CAGr or expanded G4C2r. Expression of human tau (htau4R) restored the disease-related phenotypes that had been mitigated by the loss of dtau, suggesting an evolutionarily-conserved role of tau in neurodegeneration. We further revealed that G4C2r expression increased tau accumulation by inhibiting autophagosome–lysosome fusion, possibly due to lowering the level of BAG3, a regulator of autophagy and tau. Taken together, our results reveal a novel mechanism by which expanded G4C2r causes neurodegeneration via an evolutionarily-conserved mechanism. Our findings provide novel autophagy-related mechanistic insights into C9ORF72-ALS and possible entry points to disease treatment.Electronic supplementary materialThe online version of this article (10.1007/s12264-020-00518-2) contains supplementary material, which is available to authorized users.     

Necroptotic TNFα-Syndecan 4-TNFα Vicious Cycle as a Therapeutic Target for Preventing Temporomandibular Joint Osteoarthritis

Temporomandibular joint osteoarthritis (TMJOA) is a chronic degenerative disease for which the underlying mechanism still remains unclear. Compared with apoptosis and autophagy, necroptosis causes greater harm to tissue homeostasis by releasing damage-associated molecular patterns (DAMPs). However, the role of necroptosis and downstream key DAMPs in TMJOA is unknown. Here, rodent models of TMJOA were established by the unilateral anterior crossbite (UAC). Transmission electron microscopy (TEM) and immunohistochemistry of receptor interacting protein kinase 3 (RIPK3)/phosphorylation of mixed lineage kinase domain-like protein (pMLKL) were conducted to evaluate the occurrence of necroptosis in vivo. The therapeutic effects of blocking necroptosis were achieved by intra-articularly injecting RIPK3 or MLKL inhibitors and using RIPK3 or MLKL knockout mice. In vitro necroptosis of condylar chondrocyte was induced by combination of tumor necrosis factor alpha (TNFα), second mitochondria-derived activator of caspases (SMAC) mimetics and carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]- fluoromethylketone (z-VAD-fmk). The possible DAMPs released by necroptotic chondrocytes were screened by quantitative proteomics and blocked by specific antibody. Translucent cytosol, swollen organelles, and ruptured cell membranes, features of necroptosis, were frequently manifested in chondrocytes at the early stage of condylar cartilage degeneration in TMJOA, which was accompanied by upregulation of RIPK3/pMLKL. Inhibiting or knocking out RIPK3/MLKL significantly prevented cartilage degeneration. DAMPs released by necroptotic condylar chondrocytes, such as syndecan 4 (SDC4) and heat shock protein 90 (HSP90), were verified. Furthermore, blocking the function of SDC4 significantly attenuated the expression of TNFα in cartilage and synovium, and accordingly increased cartilage thickness and reduced synovial inflammation. Thus, the necroptotic vicious cycle of TNFα-SDC4-TNFα contributes to cartilage degeneration and synovitis, and can serve as a potential therapeutic target for treating TMJOA. © 2022 American Society for Bone and Mineral Research (ASBMR).     

The effects of sodium butyrate,an inhibitor of histone deacetylase,on the cocaine- and sucrose-maintained self-administration in rats

In order to substantiate the concept that cocaine behavioral effects may be influenced by histone modification, rats were trained to self-administer cocaine intravenously (0.75 mg/(kg injection)), and were systemically pretreated with sodium butyrate (NaBu), a potent histone deacetylase inhibitor, before the test session during the maintenance phase. The effect of NaBu on a control reinforcer (sucrose)-induced self-administration was also assessed. NaBu (100–200 mg/kg) was inactive in altering the cocaine (0.75 mg/(kg injection))-maintained responding and at the highest dose (400 mg/kg) it did increase cocaine-induced lever presses during the maintenance phase. On the other hand, sucrose-reinforcing potential was not altered when NaBu was given at the highest dose (400 mg/kg). These findings extend previous observations that changes in histone acetylation are relevant to cocaine-induced behavioral effects. Given that histone acetylase inhibitor enhances cocaine-induced behavioral plasticity, the therapeutic benefits of histone acetyltransferase inhibitors warrant further investigation in the experimental models of cocaine abuse.     

Electrophysiological neurodifferentiation of subventricular zone-derived precursor cells following stroke

Stroke in rodents is associated with increased neurogenesis and the migration of newborn neurons to sites of brain ischemia, where they may participate in repair and recovery. To determine if neurogenesis following stroke yields functional new neurons, we labeled neuronal precursors in the mouse subventricular zone (SVZ) with a lentivirus-green fluorescent protein vector, produced stroke by occluding the middle cerebral artery, and detected newborn neurons 8 weeks later by fluorescence microscopy. Patch-clamp studies on fluorescent neurons in the cortical region surrounding infarction showed tetrodotoxin-sensitive Na⁺ action potentials and spontaneous excitatory post-synaptic currents, suggesting that ischemia led to functional neurogenesis with synaptic integration. These findings support the hypothesis that enhancing endogenous neurogenesis after stroke might have therapeutic benefit.     

Study of electroacupuncture with different frequencies for the treatment of headache and anxiety-depression symptoms in patients with migraine: A randomized clinical trial: 不同频率电针改善偏头痛患者头痛及焦虑抑郁症状的差异性研究-随机临床试验

ObjectiveTo observe the effects of electroacupuncture (EA) with varied frequencies on headache and anxiety-depression symptoms in patients with migraine and to screen optimal frequency of EA for patients with such conditions.DesignSingle-center, randomized, controlled clinical trial was designed, and the outcome assessors and statisticians were blinded. The patients with migraine were randomized into 2 Hz EA group, 100 Hz EA group and sham-stimulation group. In each group, the changes in migraine attacks, days with headache, the scores of visual analogy scale (VAS), self-rating anxiety scale (SAS), self-rating depression scale (SDS) and migraine-specific quality-of-life questionnaire (MSQ), as well as the dosage of analgesics were observed at the baseline, during treatment, in 1, 2 and 3 months of follow-up separately.SettingPatients were enrolled in the Third Affiliated Hospital of Zhejiang Chinese Medical University, between 1^st August 2018 and 31^st July 2021.ParticipantsSixty-five migraine patients with or without aura.InterventionsIn the EA groups, the acupoints were bilateral Fengchi (GB20), Gongxue (Extra), Sizhukong (TE23), Taiyang (EX-HN5), Shuaigu (GB8), Waiguan (TE5) and Yanglingquan (GB34). Electric stimulation was exerted at GB20 and Gongxue (Extra), with 2 Hz and 100 Hz separately. In the sham-stimulation group, the shallow acupuncture was operated at the sites 1 cm lateral to GB20 and Gongxue (Extra), and on the radial side of TE5 and GB34. The output wires were cut off after attached to the acupoints. The patients in each group received the treatment 3 times weekly, once every two days, for consecutive 4 weeks. The complete intervention was composed of 12 treatments.Main outcome measuresChanges in numbers of migraine attacks at treatment phase (week 1 to week 4) from the baseline(week -4 to week 0) in patients of each groupResults(1) Changes in migraine attacks and days with headache: In the 2 Hz EA and 100 Hz EA groups, the changes for migraine attacks and days of headache were higher significantly when compared with that in the sham-stimulation group at the same time stage (P < 0.05). There was no statistical difference between two EA groups. (2) Changes of VAS score: In the 2 Hz EA and 100 Hz EA groups, the changes of VAS score were significantly higher when compared with that in the sham-stimulation group at the same time stage (P < 0.05). There was no statistical difference between two EA groups. (3) Assessment of anxiety and depression: The differences in the changes of SAS and SDS scores had no statistical significance in patients of each group at each assessment stage (P > 0.05). (4) Assessment on the quality of life: Compared with the sham-stimulation group at the same time stage, the improvement in MSQ score was increased significantly during treatment in patients of the 2 Hz EA and 100 Hz groups (P < 0.05). There was no statistical difference between two EA groups. (5) Assessment on safety and compliance: The patients of each group had sound compliance. There was no adverse events during trial, suggesting promising safety of treatment.ConclusionEA may effectively reduce the migraine attacks, and the days and intensity of headache, presenting promising safety. However, there was no significant improvement on anxiety-depression symptoms, and no significant difference between high and low frequencies of EA treatment in relieving headache and anxiety/depression symptoms in the patients with migraine.Trial registrationChiCTR1800017259     

电针对大鼠下丘脑孤啡肽表达的影响

目的 研究电针对大鼠下丘脑孤啡肽表达的影响。方法 应用免疫组化ABC法观察大鼠下丘脑孤啡肽变化；应用RT-PCR技术观察大鼠孤啡肽前体mRNA的变化。结果 电针可以上调去卵巢大鼠下丘脑孤啡肽免疫阳性细胞数，去卵巢大鼠下丘脑孤啡肽前体mRNA含量在电针前后变化不大。结论 电针可以影响去卵巢大鼠下丘脑孤啡肽表达。     

Expression of 5-HT1A receptor mRNA in rat dorsal raphe nucleus and ventrolateral periaqueductal gray neurons after peripheral inflammation

In the present study we observed the expression of 5-hydroxytryptamine (5-HT)1A receptor mRNA in the dorsal raphe nucleus (DRN) and ventrolateral periaqueductal gray (vlPAG) neurons, especially in 5-HT immunoreactive neurons (5-HT-IR), using in situ hybridization (ISH) and double staining with fluorescent ISH (FISH) and immunohistochemical (FIH) techniques. The findings of this study demonstrated that 5-HT1A receptor mRNA was expressed with moderate to high level in the DRN and vlPAG neurons. Following carrageenan inflammation, the expression of 5-HT1A receptor mRNA in the DRN and bilateral vlPAG neurons was significantly increased. The peak occurred at 3-8h followed by a clear decrease at 24 h, which basically corresponded to the time-course of behavioral hyperalgesia. Moderate 5-HT1A receptor mRNA and 5-HT immunoreactive (5-HT-IR) double-labeled cells were observed in the DRN and vlPAG, suggesting that some of 5-HT1A receptors in the DRN and vlPAG may be autoreceptors. Eight hours after carrageenan injection, the number of the double labeled cells was significantly increased. These results suggest that the synthesis of 5-HT1A receptors, including autoreceptors, is increased in the DRN and vlPAG during peripheral inflammation.     

Spectrum of imaging appearances in Australian children with central nervous system hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare multisystem disorder characterised by the proliferation and infiltration of lymphocytes and histiocytes. Central nervous system (CNS) infiltration is particularly devastating. Neuroradiological findings have been reported predominantly as individual case reports due to the rarity of the condition. To our knowledge there have been no published studies of imaging in Australian patients. This study aimed to retrospectively describe and illustrate the MRI appearances of CNS involvement by HLH in a cohort of seven Australian children from two paediatric centres between 2000 and 2011. MRI appearances demonstrate intersubject and intrasubject variability over time, likely reflecting the severity of CNS infiltration and associated demyelination. Familiarity with MRI patterns is important for assessing and monitoring disease activity.