However, C9orf72-deficient mice do not display overt neurodegenerative phenotypes 14,18,19,22. Moreover, no studies have shown that reduced C9ORF72 activity leads to the degeneration of C9ORF72 ALS patient-derived motor neurons, nor have any provided direct evidence identifying a cellular pathway through which C9ORF72 activity modulates neuronal survival. Additionally, a patient homozygous for the C9ORF72 repeat expansion had clinical and pathological phenotypes that were severe but nonetheless did not fall outside the range of heterozygous patients, leaving it uncertain if reductions in C9ORF72 protein levels directly correlate with disease severity 23. Thus, the role of the C9ORF72 protein in C9ORF72 ALS/FTD disease pathogenesis remains unclear.
Journalistic genres in China have acquired distinctive characteristics and have shaped original sub-genres that are unique to the local journalistic tradition. While many studies analyzing their characteristics have been written in Chinese, works on the subject in other languages are still scarce. This contribution aims to fill this void by presenting the two main genres in which written journalistic production can be understood, i.e., “news” and “views”, as well as their sub-genres, and showing how they are interpreted in Chinese media studies. The analysis is based on a corpus of recent academic publications that represent the current Chinese scholarly interpretations of local genres of journalism. In doing so, the paper also offers insights on recent theoretical reflections about the functions of journalistic writing in the People’s Republic of China.
International Advisory Board: James Archibald (Translation Studies) - Hugo de Burgh (Chinese Media Studies) - Kristen Brustad (Arabic Linguistics) - Daniel Coste (French Language) - Luciano Curreri (Italian Literature) - Claudio Di Meola (German Linguistics) - Donatella Dolcini (Hindi Studies) - Johann Drumbl (German Linguistics) - Denis Ferraris (Italian Literature) - Lawrence Grossberg (Cultural Studies) - Stephen Gundle (Film and Television Studies) - Tsuchiya Junji (Sociology) - John McLeod (Post-colonial Studies) - Estrella Montolío Durán (Spanish Language) - Silvia Morgana (Italian Linguistics) - Samir Marzouki (Translation, Cultural Relations) - Mbare Ngom (Post-Colonial Literatures) - Christiane Nord (Translation Studies) - Roberto Perin (History) - Giovanni Rovere (Italian Linguistics) - Lara Ryazanova-Clarke (Russian Studies) - Shi-Xu (Discourse and Cultural Studies) - Srikant Sarangi (Discourse analysis) - Françoise Sabban, Centre d'études sur la Chine moderne et contemporaine (Chinese Studies) - Itala Vivan (Cultural Studies, Museum Studies)
An intronic GGGGCC repeat expansion in C9ORF72 is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), but its pathogenic mechanism remains unclear. Here we use human induced motor neurons (iMNs) to show that repeat-expanded C9ORF72 is haploinsufficient in ALS. We show that C9ORF72 interacts with endosomes and is required for normal vesicle trafficking and lysosomal biogenesis in motor neurons. Repeat expansion reduces C9ORF72 expression, triggering neurodegeneration through two mechanisms: accumulation of glutamate receptors leading to excitotoxicity, and impaired clearance of neurotoxic dipeptide repeat proteins derived from the repeat expansion. Thus, cooperativity between gain- and loss-of-function mechanisms leads to neurodegeneration. Restoring C9ORF72 levels or augmenting its function with constitutively active RAB5 or chemical modulators of RAB5 effectors rescues patient neuron survival and ameliorates neurodegenerative processes in both gain- and loss-of function C9ORF72 mouse models. Thus, modulating vesicle trafficking can rescue neurodegeneration caused by the C9ORF72 repeat expansion. Coupled with rare mutations in ALS2, FIG4, CHMP2B, OPTN, and SQSTM1, our results reveal mechanistic convergence on vesicle trafficking in ALS/FTD.
Live imaging of iMNs expressing a M6PR-GFP fusion protein that localizes to M6PR+ vesicles 44 confirmed that C9ORF72 patient and C9ORF72-deficient iMNs possess increased numbers of M6PR+ vesicle clusters, and that overexpression of C9ORF72 isoform A or B rescues this phenotype (Supplementary Fig. 9c-g and Supplementary Videos 5-9). Clusters did not disperse over the time course of the assay, suggesting that they are relatively stable and not in rapid flux (Supplementary Videos 5-9). In addition, M6PR+ puncta moved with a slower average speed in C9ORF72 patient and C9ORF72+/− iMNs than controls (Supplementary Fig. 9h, i). Thus, reduced C9ORF72 levels lead to fewer lysosomes in motor neurons in vitro and in vivo, and this may be due in part to altered trafficking of M6PR+ vesicles.
To verify that PIKFYVE is the functional target of the inhibitor, we first confirmed PIKFYVE expression by qPCR in control and patient (n=3 patients) iMNs (Supplementary Fig. 15b). Next, we verified that YM201636 rescued C9ORF72 patient iMN survival in a dose-dependent manner (Supplementary Fig. 15c). We then asked if Apilimod, a structurally distinct PIKFYVE inhibitor, could rescue patient iMN survival 51(Fig. 6b). To verify target engagement by Apilimod in iPSC-derived motor neurons, we administered Apilimod for three hours and measured EEA1+ early endosome size. PIKFYVE inhibition increases PI3P levels, leading to increased recruitment of EEA1 to early endosomes, more homotypic early endosomal fusion, and larger EEA1+ early endosomes 54. As expected, Apilimod treatment increased EEA1+ endosome size in a dose-dependent manner, verifying target engagement in motor neurons (Supplementary Fig. 15d, e).
The following antibodies were used in this manuscript: mouse anti-HB9 (Developmental Studies Hybridoma Bank); 81.5C10. chicken anti-TUJ1 (EMD Millipore); AB9354. rabbit anti-VACHT (Sigma); SAB4200559. rabbit anti-C9ORF72 (Sigma-Aldrich); HPA023873. rabbit anti-C9ORF72 (Proteintech); 25757–1-AP. mouse anti-EEA1 (BD Biosciences); 610457. mouse antiRAB5 (BD Biosciences); 610281. mouse anti-RAB7 (GeneTex); GTX16196. mouse anti-LAMP1 (Abcam); ab25630. mouse anti-M6PR (Abcam); ab2733. rabbit anti-GluR1 (EMD Millipore); pc246. mouse anti-NR1 (EMD Millipore); MAB363. chicken anti-GFP (GeneTex); GTX13970. rabbit anti-Glur6/7 (EMD Millipore); 04–921. mouse anti-FLAG (Sigma); F1804. mouse anti-GAPDH (Santa Cruz); sc-32233. chicken anti-MAP2 (Abcam); ab11267, rabbit anti-GLUR1 (Millipore, cat. no. 1504), mouse anti-NR1 (Novus, cat. no. NB300118), mouse anti-Transferrin receptor (Thermo, cat. no. 136800), mouse anti-LAMP3 (DSHB, cat. no. H5C6), rabbit anti-LAMP3 (Proteintech, cat. no. 12632), mouse anti-LAMP2 (DSHB, cat. no. H4B4), goat anti-HRP (Santa Cruz, cat. no. sc-47778 HRP), mouse anti-TUJ1 (Biolegend, cat. no. MMS-435P), rabbit anti-APP (Abcam, cat. no. ab32136), mouse anti-Tau5 (Thermo, cat. no. AHB0042), mouse anti-PSD-95 (Thermo, cat. no. MA1–045), mouse anti-p53 (Cell Signaling, cat. no. 2524S), anti-mouse HRP (Cell Signaling, cat. no. 7076S), anti-rabbit HRP (Cell Signaling, cat. no. 7074S).
iMNs from healthy controls and ALS patients were collected on day 21 post-transduction in RIPA buffer (Sigma-Aldrich) with a protease inhibitor cocktail (Roche). Protein quantity was measured by the BCA assay (Pierce) and samples were run on a 10% SDS gel at 4 °C. The gel was transferred onto an Immobilon membrane (Millipore). The membrane was blocked with 5% milk in 0.1% PBS-Tween 20 (PBS-T)(Sigma-Aldrich), incubated with primary antibodies overnight at 4 °C, washed three times with 0.1% PBS-T, then incubated with horseradish peroxidase (HRP)-conjugated (Santa Cruz). After three washes with 0.1% PBS-T, blots were visualized using an Amersham ECL Western Blotting Detection Kit (GE) or the SuperSignal West Femto Maximum Sensitivity Substrate (Thermo) and developed on X-ray film (Genesee). The following primary antibodies were used: rabbit anti-C9ORF72 (Proteintech, cat. no. 22637–1-AP), mouse anti-GAPDH (Santa Cruz, cat. no. sc-32233), chicken anti-MAP2 (Abcam, cat. no. ab11267), mouse anti-FLAG (Sigma, cat. no. F1804), rabbit anti-GLUR1 (Millipore, cat. no. 1504), mouse anti-NR1 (Novus, cat. no. NB300118), mouse anti-Transferrin receptor (Thermo, cat. no. 136800), mouse anti-LAMP3 (DSHB, cat. no. H5C6), rabbit anti-LAMP3 (Proteintech, cat. no. 12632), mouse anti-LAMP2 (DSHB, cat. no. H4B4), mouse anti-LAMP1 (Abcam, cat. no. Ab25630), goat anti-HRP (Santa Cruz, cat. no. sc-47778 HRP), mouse anti-EEA1 (BD Biosciences, cat. no. BD610457), mouse anti-TUJ1 (Biolegend, cat. no. MMS-435P), rabbit anti-APP (Abcam, cat. no. ab32136), mouse anti-Tau5 (Thermo, cat. no. AHB0042), mouse anti-PSD-95 (Thermo, cat. no. MA1–045) , mouse anti-p53 (Cell Signaling, cat. no. 2524S), anti-mouse HRP (Cell Signaling, cat. no. 7076S), anti-rabbit HRP (Cell Signaling, cat. no. 7074S). For C9ORF72 western blots, to generate enough motor neurons for C9ORF72 protein detection, we used a directed differentiation method described previously 28.
Immunostaining revealed that C9ORF72+/− and C9ORF72−/− iMNs contained elevated levels of NMDA (NR1) and AMPA (GLUR1) receptors on neurites and dendritic spines compared to control iMNs under basal conditions (Fig. 4a, c, d and Supplementary Fig. 5b and 10a, c-e, g, h, j, k). In addition, control iMNs treated with C9ORF72-specific ASOs displayed increased numbers of NMDA and AMPA receptors in their neurites (Supplementary Fig. 10l, m). C9ORF72 patient iMNs (n=3 patients) also showed elevated NR1 and GLUR1 levels compared to controls (n=3 controls), and forced expression of C9ORF72 isoform B reduced glutamate receptor levels in patient iMNs (n=3 patients) to that of controls (n=3 controls) (Fig. 4a-c and Supplementary Fig. 10a-h). mRNA levels of NR1 (GRIN1) and GLUR1 (GRIA1) were not elevated in flow-purified C9ORF72+/− iMNs, indicating that increased transcription could not explain the increased glutamate receptor levels (Supplementary Fig. 10n).