Novel genetic variants in MAPT and alterations in tau phosphorylation in amyotrophic lateral sclerosis post‐mortem motor cortex and cerebrospinal fluid

AbstractAlthough the molecular mechanisms underlying amyotrophic lateral sclerosis (ALS) are not yet fully understood, recent studies have described alterations in tau protein in both sporadic and familial ALS. However, it is unclear whether alterations in tau contribute to ALS pathogenesis. Here, we leveraged the ALS Knowledge Portal and Project MinE data sets and identified specific genetic variants clustering within the microtubule-binding domain of MAPT, which were unique to ALS cases. Furthermore, our analysis in a large post-mortem cohort of ALS and control motor cortex demonstrates that although there was no significant difference in the presence of phosphorylated tau (pTau) neuropil threads and neurofibrillary tangles between the two groups, pTau-S396 and pTau-S404 mis-localized to the nucleus and synapses in ALS. This was specific to the C-terminus phosphorylation sites as there was a significant decrease in pTau-T181 in ALS synaptoneurosomes compared to controls. Lastly, while there was no change in total tau or pTau-T181 in ALS CSF, there was a decrease in pTau-T181:tau ratio in ALS CSF, as previously reported. Importantly, CSF tau levels were increased in ALS patients diagnosed with bulbar onset ALS, while pTau-T181:tau ratio was decreased in ALS patients diagnosed with both bulbar and limb onset. Additionally, there was an inverse correlation between tau levels in the CSF and the revised ALS functional rating scale (ALSFRS-R) as well as a correlation between pTau-T181:tau ratio and ALSFRS-R. While there were no longitudinal alterations in tau, pTau-T181 and pTau-T181:tau ratio, there was an increase in the rate of ALSFRS-R decline per month associated with increases in tau levels. This decline was also inversely correlated with increases in pTau-T181 in relation to tau levels. Taken together, our findings demonstrate that, like Alzheimer’s disease, hyperphosphorylated tau is mis-localized in ALS and that decreases in CSF pTau-T181 may serve as a biomarker in ALS.

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A HML6 endogenous retrovirus on chromosome 3 is upregulated in amyotrophic lateral sclerosis motor cortex

Scientific Reports ◽

10.1038/s41598-021-93742-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ashley R. Jones ◽

Alfredo Iacoangeli ◽

Brett N. Adey ◽

Harry Bowles ◽

Aleksey Shatunov ◽

...

Keyword(s):

Amyotrophic Lateral Sclerosis ◽

Motor Cortex ◽

Reverse Transcriptase ◽

Endogenous Retrovirus ◽

Reverse Transcriptase Activity ◽

Endogenous Retroviruses ◽

Post Mortem ◽

Multiple Testing Correction ◽

Transcriptase Activity ◽

Lateral Sclerosis

AbstractThere is increasing evidence that endogenous retroviruses (ERVs) play a significant role in central nervous system diseases, including amyotrophic lateral sclerosis (ALS). Studies of ALS have consistently identified retroviral enzyme reverse transcriptase activity in patients. Evidence indicates that ERVs are the cause of reverse transcriptase activity in ALS, but it is currently unclear whether this is due to a specific ERV locus or a family of ERVs. We employed a combination of bioinformatic methods to identify whether specific ERVs or ERV families are associated with ALS. Using the largest post-mortem RNA-sequence datasets available we selectively identified ERVs that closely resembled full-length proviruses. In the discovery dataset there was one ERV locus (HML6_3p21.31c) that showed significant increased expression in post-mortem motor cortex tissue after multiple-testing correction. Using six replication post-mortem datasets we found HML6_3p21.31c was consistently upregulated in ALS in motor cortex and cerebellum tissue. In addition, HML6_3p21.31c showed significant co-expression with cytokine binding and genes involved in EBV, HTLV-1 and HIV type-1 infections. There were no significant differences in ERV family expression between ALS and controls. Our results support the hypothesis that specific ERV loci are involved in ALS pathology.

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Increased cerebrospinal fluid adenosine 5'-triphosphate in patients with amyotrophic lateral sclerosis

BMC Neurology ◽

10.1186/s12883-021-02288-4 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Takamasa Nukui ◽

Atsushi Matsui ◽

Hideki Niimi ◽

Tomoyuki Sugimoto ◽

Tomohiro Hayashi ◽

...

Keyword(s):

Amyotrophic Lateral Sclerosis ◽

Cerebrospinal Fluid ◽

Serum Creatinine ◽

Disease Severity ◽

Assay System ◽

Atp Levels ◽

Sum Score ◽

Highly Sensitive ◽

Severe Group ◽

Lateral Sclerosis

Abstract Background Extracellular adenosine 5'-triphosphate (ATP) has been suggested to cause neuroinflammation and motor neuron degeneration by activating microglia and astrocytes in amyotrophic lateral sclerosis (ALS). Since we have developed a highly sensitive ATP assay system, we examined cerebrospinal fluid (CSF) ATP levels in patients with ALS whether it can be a useful biomarker in ALS. Methods Forty-eight CSF samples from 44 patients with ALS were assayed for ATP with a newly established, highly sensitive assay system using luciferase luminous reaction. CSF samples from patients with idiopathic normal pressure hydrocephalus (iNPH) were assayed as a control. Patients were divided into two groups depending on their disease severity, as evaluated using the Medical Research Council (MRC) sum score. Correlations between the CSF ATP levels and other factors, including clinical data and serum creatinine levels, were evaluated. Results CSF ATP levels were significantly higher in patients with ALS than in the iNPH (716 ± 411 vs. 3635 ± 5465 pmol/L, p < 0.01). CSF ATP levels were significantly higher in the more severe group than in the iNPH group (6860 ± 8312 vs. 716 ± 411 pmol/L, p < 0.05) and mild group (6860 ± 8312 vs. 2676 ± 3959 pmol/L, p < 0.05) respectively. ALS functional rating scale-revised (ALSFRS-R) (37.9 ± 5.7 vs. 42.4 ± 2.8, p < 0.01) and serum creatinine levels (0.51 ± 0.13 vs. 0.68 ± 0.23 mg/dL, p < 0.05) were significantly lower in the severe group than in the mild group respectively. A negative correlation of CSF ATP levels with MRC sum score was demonstrated in the correlation analysis adjusted for age and sex (r = -0.3, p = 0.08). Conclusions Extracellular ATP is particularly increased in the CSF of patients with advanced ALS. CSF ATP levels may be a useful biomarker for evaluating disease severity in patients with ALS.

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Cerebrospinal Fluid Chitinases as Biomarkers for Amyotrophic Lateral Sclerosis

Diagnostics ◽

10.3390/diagnostics11071210 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1210

Author(s):

Júlia Costa ◽

Marta Gromicho ◽

Ana Pronto-Laborinho ◽

Conceição Almeida ◽

Ricardo A. Gomes ◽

...

Keyword(s):

Amyotrophic Lateral Sclerosis ◽

Cerebrospinal Fluid ◽

Motor Neurons ◽

Neurological Diseases ◽

Disease Diagnosis ◽

Enzyme Linked Immunosorbent Assay ◽

Progression Rate ◽

Therapeutic Trials ◽

Als Patients ◽

Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative neuromuscular disease that affects motor neurons controlling voluntary muscles. Survival is usually 2–5 years after onset, and death occurs due to respiratory failure. The identification of biomarkers would be very useful to help in disease diagnosis and for patient stratification based on, e.g., progression rate, with implications in therapeutic trials. Neurofilaments constitute already-promising markers for ALS and, recently, chitinases have emerged as novel marker targets for the disease. Here, we investigated cerebrospinal fluid (CSF) chitinases as potential markers for ALS. Chitotriosidase (CHIT1), chitinase-3-like protein 1 (CHI3L1), chitinase-3-like protein 2 (CHI3L2) and the benchmark marker phosphoneurofilament heavy chain (pNFH) were quantified by an enzyme-linked immunosorbent assay (ELISA) from the CSF of 34 ALS patients and 24 control patients with other neurological diseases. CSF was also analyzed by UHPLC-mass spectrometry. All three chitinases, as well as pNFH, were found to correlate with disease progression rate. Furthermore, CHIT1 was elevated in ALS patients with high diagnostic performance, as was pNFH. On the other hand, CHIT1 correlated with forced vital capacity (FVC). The three chitinases correlated with pNFH, indicating a relation between degeneration and neuroinflammation. In conclusion, our results supported the value of CHIT1 as a diagnostic and progression rate biomarker, and its potential as respiratory function marker. The results opened novel perspectives to explore chitinases as biomarkers and their functional relevance in ALS.

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