bims-axbals 2023-12-03 papers

bims-axbals

Biomed News

on Axonal biology and ALS

Issue of 2023–12–03
25 papers selected by
TJ Krzystek, ALS Therapy Development Institute

G2C4 targeting antisense oligonucleotides potently mitigate TDP-43 dysfunction in human C9orf72 ALS/FTD induced pluripotent stem cell derived neurons.
Neuronal models of TDP-43 proteinopathy display reduced axonal translation, increased oxidative stress, and defective exocytosis.
Aberrant axon initial segment plasticity and intrinsic excitability of ALS hiPSC motor neurons.
Aberrant splicing exonizes C9ORF72 repeat expansion in ALS/FTD.
Emerging role for sphingolipids in the genetics of amyotrophic lateral sclerosis.
Recurrent de novo SPTLC2 variant causes childhood-onset amyotrophic lateral sclerosis (ALS) by excess sphingolipid synthesis.
Tofersen: Silver Lining or Hyperbole??
Basal activity of PINK1 and PRKN in cell models and rodent brain.
UndERACting ion channels in neurodegeneration.
Combined RNA interference and gene replacement therapy targeting MFN2 as proof of principle for the treatment of Charcot-Marie-Tooth type 2A.
Targeting mitochondrial Ca2+ uptake for the treatment of amyotrophic lateral sclerosis.
NGLY1 mutations cause protein aggregation in human neurons.
Mendelian Randomization Identifies Genetically Supported Drug Targets for Amyotrophic Lateral Sclerosis and Frontotemporal Dementia.
Neuronal deletion of the circadian clock gene Bmal1 induces cell-autonomous dopaminergic neurodegeneration.
MLKL deficiency alleviates neuroinflammation and motor deficits in the α-synuclein transgenic mouse model of Parkinson's disease.
Leucine-rich repeat kinase 2 (LRRK2) inhibition upregulates microtubule-associated protein 1B to ameliorate lysosomal dysfunction and parkinsonism.
Altered anterograde axonal transport of mitochondria in cultured striatal neurons of a knock-in mouse model of Huntington's disease.
A guide to ERK dynamics, part 1: mechanisms and models.
Application of patient-derived induced pluripotent stem cells and organoids in inherited retinal diseases.
Screening and identification of key biomarkers associated with amyotrophic lateral sclerosis and depression using bioinformatics.
Mitophagy in human health, ageing and disease.
Targeting synapse function and loss for treatment of neurodegenerative diseases.
SIRT1-dependent mitochondrial biogenesis supports therapeutic effects of vidarabine against rotenone-induced neural cell injury.
Primary visual cortex pathology in ALS patients with C9ORF72 expansion.
On the use of thermal forces to probe kinesin's response to force.

Acta Neuropathol. 2023 Nov 29. 147(1): 1

G2C4 targeting antisense oligonucleotides potently mitigate TDP-43 dysfunction in human C9orf72 ALS/FTD induced pluripotent stem cell derived neurons.

Jeffrey D Rothstein, Victoria Baskerville, Sampath Rapuri, Emma Mehlhop, Paymaan Jafar-Nejad, Frank Rigo, Frank Bennett, Sarah Mizielinska, Adrian Isaacs, Alyssa N Coyne.

  The G4C2 repeat expansion in the C9orf72 gene is the most common genetic cause of Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Many studies suggest that dipeptide repeat proteins produced from this repeat are toxic, yet, the contribution of repeat RNA toxicity is under investigated and even less is known regarding the pathogenicity of antisense repeat RNA. Recently, two clinical trials targeting G4C2 (sense) repeat RNA via antisense oligonucleotide failed despite a robust decrease in sense-encoded dipeptide repeat proteins demonstrating target engagement. Here, in this brief report, we show that G2C4 antisense, but not G4C2 sense, repeat RNA is sufficient to induce TDP-43 dysfunction in induced pluripotent stem cell (iPSC) derived neurons (iPSNs). Unexpectedly, only G2C4, but not G4C2 sense strand targeting, ASOs mitigate deficits in TDP-43 function in authentic C9orf72 ALS/FTD patient iPSNs. Collectively, our data suggest that the G2C4 antisense repeat RNA may be an important therapeutic target and provide insights into a possible explanation for the recent G4C2 ASO clinical trial failure.

Keywords:  ALS; Antisense oligonucleotides; C9orf72; Induced pluripotent stem cell derived neurons; Repeat RNA; TDP-43

DOI:  https://doi.org/10.1007/s00401-023-02652-3
Front Cell Neurosci. 2023 ;17 1253543

Neuronal models of TDP-43 proteinopathy display reduced axonal translation, increased oxidative stress, and defective exocytosis.

Alessandra Pisciottani, Laura Croci, Fabio Lauria, Chiara Marullo, Elisa Savino, Alessandro Ambrosi, Paola Podini, Marta Marchioretto, Filippo Casoni, Ottavio Cremona, Stefano Taverna, Angelo Quattrini, Jean-Michel Cioni, Gabriella Viero, Franca Codazzi, G Giacomo Consalez.

  Amyotrophic lateral sclerosis (ALS) is a progressive, lethal neurodegenerative disease mostly affecting people around 50-60 years of age. TDP-43, an RNA-binding protein involved in pre-mRNA splicing and controlling mRNA stability and translation, forms neuronal cytoplasmic inclusions in an overwhelming majority of ALS patients, a phenomenon referred to as TDP-43 proteinopathy. These cytoplasmic aggregates disrupt mRNA transport and localization. The axon, like dendrites, is a site of mRNA translation, permitting the local synthesis of selected proteins. This is especially relevant in upper and lower motor neurons, whose axon spans long distances, likely accentuating their susceptibility to ALS-related noxae. In this work we have generated and characterized two cellular models, consisting of virtually pure populations of primary mouse cortical neurons expressing a human TDP-43 fusion protein, wt or carrying an ALS mutation. Both forms facilitate cytoplasmic aggregate formation, unlike the corresponding native proteins, giving rise to bona fide primary culture models of TDP-43 proteinopathy. Neurons expressing TDP-43 fusion proteins exhibit a global impairment in axonal protein synthesis, an increase in oxidative stress, and defects in presynaptic function and electrical activity. These changes correlate with deregulation of axonal levels of polysome-engaged mRNAs playing relevant roles in the same processes. Our data support the emerging notion that deregulation of mRNA metabolism and of axonal mRNA transport may trigger the dying-back neuropathy that initiates motor neuron degeneration in ALS.

Keywords:  TDP-43 proteinopathy; amyotrophic lateral sclerosis; axonal translation; calcium; cortical neurons; oxidative stress; polysome profiling; synaptic function

DOI:  https://doi.org/10.3389/fncel.2023.1253543
Cell Rep. 2023 Nov 28. pii: S2211-1247(23)01521-8. [Epub ahead of print]42(12): 113509

Aberrant axon initial segment plasticity and intrinsic excitability of ALS hiPSC motor neurons.

Peter Harley, Caoimhe Kerins, Ariana Gatt, Guilherme Neves, Federica Riccio, Carolina Barcellos Machado, Aimee Cheesbrough, Lea R'Bibo, Juan Burrone, Ivo Lieberam.

  Dysregulated neuronal excitability is a hallmark of amyotrophic lateral sclerosis (ALS). We sought to investigate how functional changes to the axon initial segment (AIS), the site of action potential generation, could impact neuronal excitability in ALS human induced pluripotent stem cell (hiPSC) motor neurons. We find that early TDP-43 and C9orf72 hiPSC motor neurons show an increase in the length of the AIS and impaired activity-dependent AIS plasticity that is linked to abnormal homeostatic regulation of neuronal activity and intrinsic hyperexcitability. In turn, these hyperactive neurons drive increased spontaneous myofiber contractions of in vitro hiPSC motor units. In contrast, late hiPSC and postmortem ALS motor neurons show AIS shortening, and hiPSC motor neurons progress to hypoexcitability. At a molecular level, aberrant expression of the AIS master scaffolding protein ankyrin-G and AIS-specific voltage-gated sodium channels mirror these dynamic changes in AIS function and excitability. Our results point toward the AIS as an important site of dysfunction in ALS motor neurons.

Keywords:  ALS; C9orf72; CP: Neuroscience; TDP-43; axon initial segment; fasciculations; homeostatic plasticity; human iPSC; hyperexcitability; motor neuron; motor unit; optogenetic

DOI:  https://doi.org/10.1016/j.celrep.2023.113509
bioRxiv. 2023 Nov 14. pii: 2023.11.13.566896. [Epub ahead of print]

Aberrant splicing exonizes C9ORF72 repeat expansion in ALS/FTD.

Suzhou Yang, Denethi Wijegunawardana, Udit Sheth, Austin M Veire, Juliana M S Salgado, Manasi Agrawal, Jeffrey Zhou, João D Pereira, Tania F Gendron, Junjie U Guo.

A nucleotide repeat expansion (NRE) in the first annotated intron of the C9ORF72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). While C9 NRE-containing RNAs can be translated into several toxic dipeptide repeat proteins, how an intronic NRE can assess the translation machinery in the cytoplasm remains unclear. By capturing and sequencing NRE-containing RNAs from patient-derived cells, we found that C9 NRE was exonized by the usage of downstream 5' splice sites and exported from the nucleus in a variety of spliced mRNA isoforms. C9ORF72 aberrant splicing was substantially elevated in both C9 NRE + motor neurons and human brain tissues. Furthermore, NREs above the pathological threshold were sufficient to activate cryptic splice sites in reporter mRNAs. In summary, our results revealed a crucial and potentially widespread role of repeat-induced aberrant splicing in the biogenesis, localization, and translation of NRE-containing RNAs.

DOI: https://doi.org/10.1101/2023.11.13.566896
J Neurol Neurosurg Psychiatry. 2023 Nov 24. pii: jnnp-2023-332719. [Epub ahead of print]

Emerging role for sphingolipids in the genetics of amyotrophic lateral sclerosis.

Matthew C Kiernan, Michelle Anne Farrar.



Keywords:  ALS; MOTOR NEURON DISEASE; NEUROGENETICS; NEUROMUSCULAR

DOI:  https://doi.org/10.1136/jnnp-2023-332719
J Neurol Neurosurg Psychiatry. 2023 Nov 24. pii: jnnp-2023-332132. [Epub ahead of print]

Recurrent de novo SPTLC2 variant causes childhood-onset amyotrophic lateral sclerosis (ALS) by excess sphingolipid synthesis.

Safoora B Syeda, Museer A Lone, Payam Mohassel, Sandra Donkervoort, Pinki Munot, Marcondes C França, Juan Eli Galarza-Brito, Matthias Eckenweiler, Alexander Asamoah, Kenneth Gable, Anirban Majumdar, Anke Schumann, Sita D Gupta, Arpita Lakhotia, Perry B Shieh, A Reghan Foley, Kelly E Jackson, Katherine R Chao, Thomas L Winder, Francesco Catapano, Lucy Feng, Janbernd Kirschner, Francesco Muntoni, Teresa M Dunn, Thorsten Hornemann, Carsten G Bönnemann.

   BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of the upper and lower motor neurons with varying ages of onset, progression and pathomechanisms. Monogenic childhood-onset ALS, although rare, forms an important subgroup of ALS. We recently reported specific SPTLC1 variants resulting in sphingolipid overproduction as a cause for juvenile ALS. Here, we report six patients from six independent families with a recurrent, de novo, heterozygous variant in SPTLC2 c.778G>A [p.Glu260Lys] manifesting with juvenile ALS.
METHODS: Clinical examination of the patients along with ancillary and genetic testing, followed by biochemical investigation of patients' blood and fibroblasts, was performed.
RESULTS: All patients presented with early-childhood-onset progressive weakness, with signs and symptoms of upper and lower motor neuron degeneration in multiple myotomes, without sensory neuropathy. These findings were supported on ancillary testing including nerve conduction studies and electromyography, muscle biopsies and muscle ultrasound studies. Biochemical investigations in plasma and fibroblasts showed elevated levels of ceramides and unrestrained de novo sphingolipid synthesis. Our studies indicate that SPTLC2 variant [c.778G>A, p.Glu260Lys] acts distinctly from hereditary sensory and autonomic neuropathy (HSAN)-causing SPTLC2 variants by causing excess canonical sphingolipid biosynthesis, similar to the recently reported SPTLC1 ALS associated pathogenic variants. Our studies also indicate that serine supplementation, which is a therapeutic in SPTLC1 and SPTCL2-associated HSAN, is expected to exacerbate the excess sphingolipid synthesis in serine palmitoyltransferase (SPT)-associated ALS.
CONCLUSIONS: SPTLC2 is the second SPT-associated gene that underlies monogenic, juvenile ALS and further establishes alterations of sphingolipid metabolism in motor neuron disease pathogenesis. Our findings also have important therapeutic implications: serine supplementation must be avoided in SPT-associated ALS, as it is expected to drive pathogenesis further.

Keywords:  ALS; BIOCHEMISTRY; MOTOR NEURON DISEASE; NEUROGENETICS; NEUROMUSCULAR

DOI:  https://doi.org/10.1136/jnnp-2023-332132
Ann Indian Acad Neurol. 2023 Sep-Oct;26(5):26(5): 638-640

Tofersen: Silver Lining or Hyperbole??

Tanushree Chawla, Vinay Goyal.

  Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder of anterior horn cells with a dismal prognosis. Over a century since its description, we still do not have a cure for this disorder. Edaravone, Riluzole, and combination of phenylbutyrate and taurursodiol are a handful of FDA-approved drugs that only delay the progression of the disease by a few months. Tofersen, an antisense oligonucleotide, in SOD1 related ALS, has joined the bandwagon of FDA-approved drugs for ALS recently. It is a gene therapy that has been found to lower SOD1 concentrations and neurofilament light chain concentrations in blood and CSF, a known biomarker of ALS, leading to the accelerated approval of the drug. Although it did not show any statistically significant clinical improvement. In this article, we discuss the development and approval process of the first gene-based therapy, Tofersen, for ALS.

Keywords:  Amyotrophic lateral sclerosis; SOD1-related ALS; Tofersen; gene therapy

DOI:  https://doi.org/10.4103/aian.aian_734_23
Autophagy. 2023 Dec 02. 1-12

Basal activity of PINK1 and PRKN in cell models and rodent brain.

Jens O Watzlawik, Fabienne C Fiesel, Gabriella Fiorino, Bernardo A Bustillos, Zahra Baninameh, Briana N Markham, Xu Hou, Caleb S Hayes, Jenny M Bredenberg, Nicholas W Kurchaba, Dominika Fričová, Joanna Siuda, Zbigniew K Wszolek, Sachiko Noda, Shigeto Sato, Nobutaka Hattori, Asheeta A Prasad, Deniz Kirik, Howard S Fox, Kelly L Stauch, Matthew S Goldberg, Wolfdieter Springer.

  The ubiquitin kinase-ligase pair PINK1-PRKN recognizes and transiently labels damaged mitochondria with ubiquitin phosphorylated at Ser65 (p-S65-Ub) to mediate their selective degradation (mitophagy). Complete loss of PINK1 or PRKN function unequivocally leads to early-onset Parkinson disease, but it is debated whether impairments in mitophagy contribute to disease later in life. While the pathway has been extensively studied in cell culture upon acute and massive mitochondrial stress, basal levels of activation under endogenous conditions and especially in vivo in the brain remain undetermined. Using rodent samples, patient-derived cells, and isogenic neurons, we here identified age-dependent, brain region-, and cell type-specific effects and determined expression levels and extent of basal and maximal activation of PINK1 and PRKN. Our work highlights the importance of defining critical risk and therapeutically relevant levels of PINK1-PRKN signaling which will further improve diagnosis and prognosis and will lead to better stratification of patients for future clinical trials.

Keywords:  Mitophagy; PINK1; PRKN; Parkinson disease; parkin; ubiquitin

DOI:  https://doi.org/10.1080/15548627.2023.2286414
Trends Neurosci. 2023 Nov 29. pii: S0166-2236(23)00262-X. [Epub ahead of print]

UndERACting ion channels in neurodegeneration.

Matisse T Jacobs, Rebecca San Gil, Adam K Walker.

  In a recent study, Guo and colleagues characterised the function of an elusive endoplasmic reticulum (ER) anion channel protein, Chloride Channel CLiC Like 1 (CLCC1), and identified rare CLCC1 variants in people with amyotrophic lateral sclerosis (ALS). CLCC1 mutants disrupted ER function in vitro and promoted ALS-like pathology and neurodegeneration in mice. This work reveals a previously uncharacterised pathway involved in ER calcium release and highlights new pathogenic mechanisms underlying neurodegeneration.

Keywords:  TDP-43; amyotrophic lateral sclerosis; chloride channel; endoplasmic reticulum; integrated stress response

DOI:  https://doi.org/10.1016/j.tins.2023.11.002
Cell Mol Life Sci. 2023 Nov 25. 80(12): 373

Combined RNA interference and gene replacement therapy targeting MFN2 as proof of principle for the treatment of Charcot-Marie-Tooth type 2A.

Federica Rizzo, Silvia Bono, Marc David Ruepp, Sabrina Salani, Linda Ottoboni, Elena Abati, Valentina Melzi, Chiara Cordiglieri, Serena Pagliarani, Roberta De Gioia, Alessia Anastasia, Michela Taiana, Manuela Garbellini, Simona Lodato, Paolo Kunderfranco, Daniele Cazzato, Daniele Cartelli, Caterina Lonati, Nereo Bresolin, Giacomo Comi, Monica Nizzardo, Stefania Corti.

  Mitofusin-2 (MFN2) is an outer mitochondrial membrane protein essential for mitochondrial networking in most cells. Autosomal dominant mutations in the MFN2 gene cause Charcot-Marie-Tooth type 2A disease (CMT2A), a severe and disabling sensory-motor neuropathy that impacts the entire nervous system. Here, we propose a novel therapeutic strategy tailored to correcting the root genetic defect of CMT2A. Though mutant and wild-type MFN2 mRNA are inhibited by RNA interference (RNAi), the wild-type protein is restored by overexpressing cDNA encoding functional MFN2 modified to be resistant to RNAi. We tested this strategy in CMT2A patient-specific human induced pluripotent stem cell (iPSC)-differentiated motor neurons (MNs), demonstrating the correct silencing of endogenous MFN2 and replacement with an exogenous copy of the functional wild-type gene. This approach significantly rescues the CMT2A MN phenotype in vitro, stabilizing the altered axonal mitochondrial distribution and correcting abnormal mitophagic processes. The MFN2 molecular correction was also properly confirmed in vivo in the MitoCharc1 CMT2A transgenic mouse model after cerebrospinal fluid (CSF) delivery of the constructs into newborn mice using adeno-associated virus 9 (AAV9). Altogether, our data support the feasibility of a combined RNAi and gene therapy strategy for treating the broad spectrum of human diseases associated with MFN2 mutations.

Keywords:  CMT2A; Gene therapy; MFN2; MitoCharc1; Motor neuron; RNA interfering

DOI:  https://doi.org/10.1007/s00018-023-05018-w
J Physiol. 2023 Nov 27.

Targeting mitochondrial Ca2+ uptake for the treatment of amyotrophic lateral sclerosis.

Renjia Zhong, Michael T Rua, Lan Wei-LaPierre.

  Amyotrophic lateral sclerosis (ALS) is a rare adult-onset neurodegenerative disease characterized by progressive motor neuron (MN) loss, muscle denervation and paralysis. Over the past several decades, researchers have made tremendous efforts to understand the pathogenic mechanisms underpinning ALS, with much yet to be resolved. ALS is described as a non-cell autonomous condition with pathology detected in both MNs and non-neuronal cells, such as glial cells and skeletal muscle. Studies in ALS patient and animal models reveal ubiquitous abnormalities in mitochondrial structure and function, and disturbance of intracellular calcium homeostasis in various tissue types, suggesting a pivotal role of aberrant mitochondrial calcium uptake and dysfunctional calcium signalling cascades in ALS pathogenesis. Calcium signalling and mitochondrial dysfunction are intricately related to the manifestation of cell death contributing to MN loss and skeletal muscle dysfunction. In this review, we discuss the potential contribution of intracellular calcium signalling, particularly mitochondrial calcium uptake, in ALS pathogenesis. Functional consequences of excessive mitochondrial calcium uptake and possible therapeutic strategies targeting mitochondrial calcium uptake or the mitochondrial calcium uniporter, the main channel mediating mitochondrial calcium influx, are also discussed.

Keywords:  ALS; mitochondria calcium; motor neuron; skeletal muscle; therapeutic target

DOI:  https://doi.org/10.1113/JP284143
Cell Rep. 2023 Nov 30. pii: S2211-1247(23)01478-X. [Epub ahead of print]42(12): 113466

NGLY1 mutations cause protein aggregation in human neurons.

Andreea Manole, Thomas Wong, Amanda Rhee, Sammy Novak, Shao-Ming Chin, Katya Tsimring, Andres Paucar, April Williams, Traci Fang Newmeyer, Simon T Schafer, Idan Rosh, Susmita Kaushik, Rene Hoffman, Songjie Chen, Guangwen Wang, Michael Snyder, Ana Maria Cuervo, Leo Andrade, Uri Manor, Kevin Lee, Jeffrey R Jones, Shani Stern, Maria C Marchetto, Fred H Gage.

  Biallelic mutations in the gene that encodes the enzyme N-glycanase 1 (NGLY1) cause a rare disease with multi-symptomatic features including developmental delay, intellectual disability, neuropathy, and seizures. NGLY1's activity in human neural cells is currently not well understood. To understand how NGLY1 gene loss leads to the specific phenotypes of NGLY1 deficiency, we employed direct conversion of NGLY1 patient-derived induced pluripotent stem cells (iPSCs) to functional cortical neurons. Transcriptomic, proteomic, and functional studies of iPSC-derived neurons lacking NGLY1 function revealed several major cellular processes that were altered, including protein aggregate-clearing functionality, mitochondrial homeostasis, and synaptic dysfunctions. These phenotypes were rescued by introduction of a functional NGLY1 gene and were observed in iPSC-derived mature neurons but not astrocytes. Finally, laser capture microscopy followed by mass spectrometry provided detailed characterization of the composition of protein aggregates specific to NGLY1-deficient neurons. Future studies will harness this knowledge for therapeutic development.

Keywords:  CP: Neuroscience; NGLY1 deficiency; chaperones; fragmented mitochondria; neural cells; organoids; protein aggregates

DOI:  https://doi.org/10.1016/j.celrep.2023.113466
Mol Neurobiol. 2023 Nov 29.

Mendelian Randomization Identifies Genetically Supported Drug Targets for Amyotrophic Lateral Sclerosis and Frontotemporal Dementia.

Yahui Zhu, Mao Li, Hongfen Wang, Fei Yang, RongRong Du, Xinyuan Pang, Jiongming Bai, Xusheng Huang.

  Currently, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) have no effective treatments. Drug repurposing offers a rapid method to meet therapeutic need for ALS and FTD. To identify therapeutic targets associated with ALS and FTD, Mendelian randomization (MR) analysis and colocalization were performed. Genetic instruments were based on transcriptomic and proteomic data for 422 actionable proteins targeted by approved drugs or clinical drug candidates. The publicly available ALS GWAS summary data (including a total of 20,806 ALS cases and 59,804 controls) and FTD GWAS summary data (including a total of 2154 patients with FTD and 4308 controls) were used. Using cis-expression quantitative trait loci and cis-protein quantitative trait loci genetic instruments, we identified several drug targets for repurposing (ALS: MARK3, false-discovery rate (FDR) = 0.043; LTBR, FDR = 0.068) (FTD: HLA-DRB1, FDR = 0.083; ADH5, FDR = 0.056). Our MR study analyzed the actionable druggable proteins and provided potential therapeutic targets for ALS and FTD. Future studies should further elucidate the underlying mechanism of corresponding drug targets in the pathogenesis of ALS and FTD.

Keywords:  Amyotrophic lateral sclerosis; Drug targets; Frontotemporal dementia; Mendelian randomization

DOI:  https://doi.org/10.1007/s12035-023-03817-7
JCI Insight. 2023 Nov 30. pii: e162771. [Epub ahead of print]

Neuronal deletion of the circadian clock gene Bmal1 induces cell-autonomous dopaminergic neurodegeneration.

Michael K Kanan, Patrick W Sheehan, Jessica N Haines, Pedro G Gomez, Adya Dhuler, Collin J Nadarajah, Zachary M Wargel, Brittany M Freeberg, Hemanth R Nelvagal, Mariko Izumo, Joseph S Takahashi, Jonathan D Cooper, Albert A Davis, Erik S Musiek.

  Circadian rhythm dysfunction is a hallmark of Parkinson Disease (PD), and diminished expression of the core clock gene Bmal1 has been described in PD patients. BMAL1 is required for core circadian clock function, but also serves non-rhythmic functions. Germline Bmal1 deletion can cause brain oxidative stress and synapse loss in mice, and can exacerbate dopaminergic neurodegeneration in response to the toxin MPTP. Here we examined the impact of cell type-specific Bmal1 deletion on dopaminergic neuron viability in vivo. We observed that global, post-natal deletion of Bmal1 caused spontaneous loss of tyrosine hydroxylase-positive (TH+) dopaminergic neurons in the substantia nigra pars compacta (SNpc). This was not replicated by light-induced disruption of behavioral circadian rhythms, and was not induced by astrocyte- or microglia-specific Bmal1 deletion. However, either pan-neuronal or TH neuron-specific Bmal1 deletion caused cell-autonomous loss of TH+ neurons in the SNpc. Bmal1 deletion did not change the percentage of TH neuron loss after alpha-synuclein fibril injection, though Bmal1 KO mice had fewer TH neurons at baseline. Transcriptomic analysis revealed dysregulation of pathways involved in oxidative phosphorylation and Parkinson Disease. These findings demonstrate a cell-autonomous role for BMAL1 in regulating dopaminergic neuronal survival, and may have important implications for neuroprotection in PD.

Keywords:  Aging; Neurodegeneration; Neuroscience; Parkinson disease

DOI:  https://doi.org/10.1172/jci.insight.162771
Mol Neurodegener. 2023 Dec 01. 18(1): 94

MLKL deficiency alleviates neuroinflammation and motor deficits in the α-synuclein transgenic mouse model of Parkinson's disease.

Lu Geng, Wenqing Gao, Hexige Saiyin, Yuanyuan Li, Yu Zeng, Zhifei Zhang, Xue Li, Zuolong Liu, Qiang Gao, Ping An, Ning Jiang, Xiaofei Yu, Xiangjun Chen, Suhua Li, Lei Chen, Boxun Lu, Aiqun Li, Guoyuan Chen, Yidong Shen, Haibing Zhang, Mei Tian, Zhuohua Zhang, Jixi Li.

  Parkinson's disease (PD), one of the most devastating neurodegenerative brain disorders, is characterized by the progressive loss of dopaminergic neurons in the substantia nigra (SN) and deposits of α-synuclein aggregates. Currently, pharmacological interventions for PD remain inadequate. The cell necroptosis executor protein MLKL (Mixed-lineage kinase domain-like) is involved in various diseases, including inflammatory bowel disease and neurodegenerative diseases; however, its precise role in PD remains unclear. Here, we investigated the neuroprotective role of MLKL inhibition or ablation against primary neuronal cells and human iPSC-derived midbrain organoids induced by toxic α-Synuclein preformed fibrils (PFFs). Using a mouse model (Tg-Mlkl-/-) generated by crossbreeding the SNCA A53T synuclein transgenic mice with MLKL knockout (KO)mice, we assessed the impact of MLKL deficiency on the progression of Parkinsonian traits. Our findings demonstrate that Tg-Mlkl-/- mice exhibited a significant improvement in motor symptoms and reduced phosphorylated α-synuclein expression compared to the classic A53T transgenic mice. Furthermore, MLKL deficiency alleviated tyrosine hydroxylase (TH)-positive neuron loss and attenuated neuroinflammation by inhibiting the activation of microglia and astrocytes. Single-cell RNA-seq (scRNA-seq) analysis of the SN of Tg-Mlkl-/- mice revealed a unique cell type-specific transcriptome profile, including downregulated prostaglandin D synthase (PTGDS) expression, indicating reduced microglial cells and dampened neuron death. Thus, MLKL represents a critical therapeutic target for reducing neuroinflammation and preventing motor deficits in PD.

Keywords:  MLKL; Neuroinflammation; Parkinson’s disease; Tg-Mlkl −/− mice; scRNA-seq

DOI:  https://doi.org/10.1186/s13024-023-00686-5
MedComm (2020). 2023 Dec;4(6): e429

Leucine-rich repeat kinase 2 (LRRK2) inhibition upregulates microtubule-associated protein 1B to ameliorate lysosomal dysfunction and parkinsonism.

Kang Chen, Fei Tang, Bin Du, Zhe-Zhou Yue, Ling-Ling Jiao, Xu-Long Ding, Qing-Zhang Tuo, Jie Meng, Si-Yu He, Lunzhi Dai, Peng Lei, Xia-Wei Wei.

  Mutations in LRRK2 (encoding leucine-rich repeat kinase 2 protein, LRRK2) are the most common genetic risk factors for Parkinson's disease (PD), and increased LRRK2 kinase activity was observed in sporadic PD. Therefore, inhibition of LRRK2 has been tested as a disease-modifying therapeutic strategy using the LRRK2 mutant mice and sporadic PD. Here, we report a newly designed molecule, FL090, as a LRRK2 kinase inhibitor, verified in cell culture and animal models of PD. Using the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mice and SNCA A53T transgenic mice, FL090 ameliorated motor dysfunctions, reduced LRRK2 kinase activity, and rescued loss in the dopaminergic neurons in the substantia nigra. Notably, by RNA-Seq analysis, we identified microtubule-associated protein 1 (MAP1B) as a crucial mediator of FL090's neuroprotective effects and found that MAP1B and LRRK2 co-localize. Overexpression of MAP1B rescued 1-methyl-4-phenylpyridinium induced cytotoxicity through rescuing the lysosomal function, and the protective effect of FL090 was lost in MAP1B knockout cells. Further studies may be focused on the in vivo mechanisms of MAP1B and microtubule function in PD. Collectively, these findings highlight the potential of FL090 as a therapeutic agent for sporadic PD and familial PD without LRRK2 mutations.

Keywords:  A53T; LRRK2; MAP1B; MPTP; Parkinson's disease

DOI:  https://doi.org/10.1002/mco2.429
Biochem Biophys Res Commun. 2023 Nov 18. pii: S0006-291X(23)01340-2. [Epub ahead of print]691 149246

Altered anterograde axonal transport of mitochondria in cultured striatal neurons of a knock-in mouse model of Huntington's disease.

Chao Wu, Haoran Yin, Songdi Fu, Hanna Yoo, Min Zhang, Hyokeun Park.

  Huntington's disease (HD) is a progressive genetic neurodegenerative disease caused by an abnormal expansion of a cytosine-adenine-guanine trinucleotide repeat in the huntingtin gene. One pathological feature of HD is neuronal loss in the striatum. Despite many efforts, mechanisms underlying neuronal loss in HD striatum remain elusive. It was suggested that the mutant huntingtin protein interacts mitochondrial proteins and causes mitochondrial dysfunction in striatal neurons. However, whether axonal transport of mitochondria is altered in HD striatal neurons remains controversial. Here, we examined axonal transport of single mitochondria labelled with Mito-DsRed2 in cultured striatal neurons of zQ175 knock-in mice (a knock-in mouse model of HD). We observed decreased anterograde axonal transport of proximal mitochondria in HD striatal neurons compared with wild-type (WT) striatal neurons. Decreased anterograde transport in HD striatal neurons was prevented by overexpressing mitochondrial Rho GTPase 1 (Miro1). Our results offer a new insight into mechanisms underlying neuronal loss in the striatum in HD.

Keywords:  Axonal transport; Huntington's disease; Miro1; Mitochondria; Neurodegenerative disease; Real-time imaging

DOI:  https://doi.org/10.1016/j.bbrc.2023.149246
Biochem J. 2023 Dec 13. 480(23): 1887-1907

A guide to ERK dynamics, part 1: mechanisms and models.

Abhineet Ram, Devan Murphy, Nicholaus DeCuzzi, Madhura Patankar, Jason Hu, Michael Pargett, John G Albeck.

  Extracellular signal-regulated kinase (ERK) has long been studied as a key driver of both essential cellular processes and disease. A persistent question has been how this single pathway is able to direct multiple cell behaviors, including growth, proliferation, and death. Modern biosensor studies have revealed that the temporal pattern of ERK activity is highly variable and heterogeneous, and critically, that these dynamic differences modulate cell fate. This two-part review discusses the current understanding of dynamic activity in the ERK pathway, how it regulates cellular decisions, and how these cell fates lead to tissue regulation and pathology. In part 1, we cover the optogenetic and live-cell imaging technologies that first revealed the dynamic nature of ERK, as well as current challenges in biosensor data analysis. We also discuss advances in mathematical models for the mechanisms of ERK dynamics, including receptor-level regulation, negative feedback, cooperativity, and paracrine signaling. While hurdles still remain, it is clear that higher temporal and spatial resolution provide mechanistic insights into pathway circuitry. Exciting new algorithms and advanced computational tools enable quantitative measurements of single-cell ERK activation, which in turn inform better models of pathway behavior. However, the fact that current models still cannot fully recapitulate the diversity of ERK responses calls for a deeper understanding of network structure and signal transduction in general.

Keywords:  biological networks; computational models; epidermal growth factor receptor; extracellular signal-regulated kinases; mitogen-activated protein kinases; receptor tyrosine kinases

DOI:  https://doi.org/10.1042/BCJ20230276
Stem Cell Res Ther. 2023 Nov 27. 14(1): 340

Application of patient-derived induced pluripotent stem cells and organoids in inherited retinal diseases.

Yuqin Liang, Xihao Sun, Chunwen Duan, Shibo Tang, Jiansu Chen.

  Inherited retinal diseases (IRDs) can induce severe sight-threatening retinal degeneration and impose a considerable economic burden on patients and society, making efforts to cure blindness imperative. Transgenic animals mimicking human genetic diseases have long been used as a primary research tool to decipher the underlying pathogenesis, but there are still some obvious limitations. As an alternative strategy, patient-derived induced pluripotent stem cells (iPSCs), particularly three-dimensional (3D) organoid technology, are considered a promising platform for modeling different forms of IRDs, including retinitis pigmentosa, Leber congenital amaurosis, X-linked recessive retinoschisis, Batten disease, achromatopsia, and best vitelliform macular dystrophy. Here, this paper focuses on the status of patient-derived iPSCs and organoids in IRDs in recent years concerning disease modeling and therapeutic exploration, along with potential challenges for translating laboratory research to clinical application. Finally, the importance of human iPSCs and organoids in combination with emerging technologies such as multi-omics integration analysis, 3D bioprinting, or microfluidic chip platform are highlighted. Patient-derived retinal organoids may be a preferred choice for more accurately uncovering the mechanisms of human retinal diseases and will contribute to clinical practice.

Keywords:  Disease modeling; Induced pluripotent stem cell; Inherited retinal disease; Retinal organoid; Tissue engineering

DOI:  https://doi.org/10.1186/s13287-023-03564-5
Medicine (Baltimore). 2023 Nov 24. 102(47): e36265

Screening and identification of key biomarkers associated with amyotrophic lateral sclerosis and depression using bioinformatics.

Ziyue Wang, Hao Yang, Yu Han, Jing Teng, Xinru Kong, Xianghua Qi.

This study aims to identify common molecular biomarkers between amyotrophic lateral sclerosis (ALS) and depression using bioinformatics methods, in order to provide potential targets and new ideas and methods for the diagnosis and treatment of these diseases. Microarray datasets GSE139384, GSE35978 and GSE87610 were obtained from the Gene Expression Omnibus (GEO) database, and differentially expressed genes (DEGs) between ALS and depression were identified. After screening for overlapping DEGs, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed. Furthermore, a protein-protein interaction (PPI) network was constructed using the STRING database and Cytoscape software, and hub genes were identified. Finally, a network between miRNAs and hub genes was constructed using the NetworkAnalyst tool, and possible key miRNAs were predicted. A total of 357 genes have been identified as common DEGs between ALS and depression. GO and KEGG enrichment analyses of the 357 DEGs showed that they were mainly involved in cytoplasmic translation. Further analysis of the PPI network using Cytoscape and MCODE plugins identified 6 hub genes, including mitochondrial ribosomal protein S12 (MRPS12), poly(rC) binding protein 1 (PARP1), SNRNP200, PCBP1, small G protein signaling modulator 1 (SGSM1), and DNA methyltransferase 1 (DNMT1). Five possible target miRNAs, including miR-221-5p, miR-21-5p, miR-100-5p, miR-30b-5p, and miR-615-3p, were predicted by constructing a miRNA-gene network. This study used bioinformatics techniques to explore the potential association between ALS and depression, and identified potential biomarkers. These biomarkers may provide new ideas and methods for the early diagnosis, treatment, and monitoring of ALS and depression.

DOI: https://doi.org/10.1097/MD.0000000000036265
Nat Metab. 2023 Nov 30.

Mitophagy in human health, ageing and disease.

Anna Picca, Julie Faitg, Johan Auwerx, Luigi Ferrucci, Davide D'Amico.

Maintaining optimal mitochondrial function is a feature of health. Mitophagy removes and recycles damaged mitochondria and regulates the biogenesis of new, fully functional ones preserving healthy mitochondrial functions and activities. Preclinical and clinical studies have shown that impaired mitophagy negatively affects cellular health and contributes to age-related chronic diseases. Strategies to boost mitophagy have been successfully tested in model organisms, and, recently, some have been translated into clinics. In this Review, we describe the basic mechanisms of mitophagy and how mitophagy can be assessed in human blood, the immune system and tissues, including muscle, brain and liver. We outline mitophagy's role in specific diseases and describe mitophagy-activating approaches successfully tested in humans, including exercise and nutritional and pharmacological interventions. We describe how mitophagy is connected to other features of ageing through general mechanisms such as inflammation and oxidative stress and forecast how strengthening research on mitophagy and mitophagy interventions may strongly support human health.

DOI: https://doi.org/10.1038/s42255-023-00930-8
Nat Rev Drug Discov. 2023 Nov 27.

Targeting synapse function and loss for treatment of neurodegenerative diseases.

Borislav Dejanovic, Morgan Sheng, Jesse E Hanson.

Synapse dysfunction and loss are hallmarks of neurodegenerative diseases that correlate with cognitive decline. However, the mechanisms and therapeutic strategies to prevent or reverse synaptic damage remain elusive. In this Review, we discuss recent advances in understanding the molecular and cellular pathways that impair synapses in neurodegenerative diseases, including the effects of protein aggregation and neuroinflammation. We also highlight emerging therapeutic approaches that aim to restore synaptic function and integrity, such as enhancing synaptic plasticity, preventing synaptotoxicity, modulating neuronal network activity and targeting immune signalling. We discuss the preclinical and clinical evidence for each strategy, as well as the challenges and opportunities for developing effective synapse-targeting therapeutics for neurodegenerative diseases.

DOI: https://doi.org/10.1038/s41573-023-00823-1
Heliyon. 2023 Nov;9(11): e21695

SIRT1-dependent mitochondrial biogenesis supports therapeutic effects of vidarabine against rotenone-induced neural cell injury.

Lanxin Li, Yang Zhang, Zhengqian Chen, Ruyong Yao, Zhongqiu Xu, Can Xu, Fujie He, Haitao Pei, Cui Hao.

  Parkinson's disease (PD) is the second most common neurodegenerative disease in the world, which is distinguished by the loss of dopaminergic (DA) neurons in the substantia nigra and the formation of intraneuronal. Numerous studies showed that the damage and dysfunction of mitochondria may play key roles in DA neuronal loss. Thus, it is necessary to seek therapeutic measures for PD targeting mitochondrial function and biogenesis. In this study, through screening the purchased compound library, we found that marine derived vidarabine had significant neuroprotective effects against rotenone (ROT) induced SH-SY5Y cell injury. Further studies indicated that vidarabine pretreatment significantly protected ROT-treated SH-SY5Y cells from toxicity by preserving mitochondrial morphology, improving mitochondrial function, and reducing cell apoptosis. Vidarabine also reduced the oxidative stress and increased the expression levels of PGC-1α, NRF1, and TFAM proteins, which was accompanied by the increased mitochondrial biogenesis. However, the neuroprotective effects of vidarabine were counteracted in the presence of SIRT1-specific inhibitor Ex-527. Besides, vidarabine treatment attenuated the weight loss, alleviated the motor deficits and inhibited the neuronal injury in the MPTP induced mouse model. Thus, vidarabine may exert neuroprotective effects via a mechanism involving specific connections between the SIRT1-dependent mitochondrial biogenesis and its antioxidant capacity, suggesting that vidarabine has potential to be developed into a novel therapeutic agent for PD.

Keywords:  Parkinson's disease; SH-SY5Y cells; SIRT1; mitochondrial biogenesis; oxidative stress

DOI:  https://doi.org/10.1016/j.heliyon.2023.e21695
Brain Pathol. 2023 Nov 27. e13229

Primary visual cortex pathology in ALS patients with C9ORF72 expansion.

Matthew D Cykowski, Anithachristy S Arumanayagam, Suzanne Z Powell, Stanley H Appel.

  Poly-GA and poly-GP immunofluorescence studies show conspicuous dipeptide repeat pathology in layers IV and II of primary visual cortex in C9ALS patients.

Keywords:  ALS; C9ORF72; TDP-43; calcium-binding protein; dipeptide repeat; visual cortex

DOI:  https://doi.org/10.1111/bpa.13229
Front Mol Biosci. 2023 ;10 1260914

On the use of thermal forces to probe kinesin's response to force.

Chuan Chang, Tiantian Zheng, Guilherme Nettesheim, Hayoung Song, Changhyun Cho, Samuele Crespi, George Shubeita.

  The stepping dynamics of cytoskeletal motor proteins determines the dynamics of cargo transport. In its native cellular environment, a molecular motor is subject to forces from several sources including thermal forces and forces ensuing from the interaction with other motors bound to the same cargo. Understanding how the individual motors respond to these forces can allow us to predict how they move their cargo when part of a team. Here, using simulation, we show that details of how the kinesin motor responds to small assisting forces-which, at the moment, are not experimentally constrained-can lead to significant changes in cargo dynamics. Using different models of the force-dependent detachment probability of the kinesin motor leads to different predictions on the run-length of the cargo they carry. These differences emerge from the thermal forces acting on the cargo and transmitted to the motor through the motor tail that tethers the motor head to the microtubule. We show that these differences appear for cargo carried by individual motors or motor teams, and use our findings to propose the use of thermal forces as a probe of kinesin's response to force in this otherwise inaccessible force regime.

Keywords:  intracellular transport; kinesin; molecular motors; motor force response; motor runlength; thermal forces

DOI:  https://doi.org/10.3389/fmolb.2023.1260914