PolyGR and polyPR knock-in mice reveal a conserved neuroprotective extracellular matrix signature in C9orf72 ALS/FTD neurons

Dipeptide repeat proteins are a major pathogenic feature of C9orf72 amyotrophic lateral sclerosis (C9ALS)/frontotemporal dementia (FTD) pathology, but their physiological impact has yet to be fully determined. Here we generated C9orf72 dipeptide repeat knock-in mouse models characterized by expression of 400 codon-optimized polyGR or polyPR repeats, and heterozygous C9orf72 reduction. (GR)400 and (PR)400 knock-in mice recapitulate key features of C9ALS/FTD, including cortical neuronal hyperexcitability, age-dependent spinal motor neuron loss and progressive motor dysfunction. Quantitative proteomics revealed an increase in extracellular matrix (ECM) proteins in (GR)400 and (PR)400 spinal cord, with the collagen COL6A1 the most increased protein. TGF-β1 was one of the top predicted regulators of this ECM signature and polyGR expression in human induced pluripotent stem cell neurons was sufficient to induce TGF-β1 followed by COL6A1. Knockdown of TGF-β1 or COL6A1 orthologues in polyGR model Drosophila exacerbated neurodegeneration, while expression of TGF-β1 or COL6A1 in induced pluripotent stem cell-derived motor neurons of patients with C9ALS/FTD protected against glutamate-induced cell death. Altogether, our findings reveal a neuroprotective and conserved ECM signature in C9ALS/FTD.

A monocarboxylate transporter rescues frontotemporal dementia and Alzheimer's disease models

Brains are highly metabolically active organs, consuming 20% of a person's energy at resting state. A decline in glucose metabolism is a common feature across a number of neurodegenerative diseases. Another common feature is the progressive accumulation of insoluble protein deposits, it's unclear if the two are linked. Glucose metabolism in the brain is highly coupled between neurons and glia, with glucose taken up by glia and metabolised to lactate, which is then shuttled via transporters to neurons, where it is converted back to pyruvate and fed into the TCA cycle for ATP production. Monocarboxylates are also involved in signalling, and play broad ranging roles in brain homeostasis and metabolic reprogramming. However, the role of monocarboxylates in dementia has not been tested. Here, we find that increasing pyruvate import in Drosophila neurons by over-expression of the transporter bumpel, leads to a rescue of lifespan and behavioural phenotypes in fly models of both frontotemporal dementia and Alzheimer's disease. The rescue is linked to a clearance of late stage autolysosomes, leading to degradation of toxic peptides associated with disease. We propose upregulation of pyruvate import into neurons as potentially a broad-scope therapeutic approach to increase neuronal autophagy, which could be beneficial for multiple dementias.

Toxicity of C9orf72-associated dipeptide repeat peptides is modified by commonly used protein tags

Hexanucleotide repeat expansions in the C9orf72 gene are the most prevalent genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Transcripts of the expansions are translated into toxic dipeptide repeat (DPR) proteins. Most preclinical studies in cell and animal models have used protein-tagged polyDPR constructs to investigate DPR toxicity but the effects of tags on DPR toxicity have not been systematically explored. Here, we used Drosophila to assess the influence of protein tags on DPR toxicity. Tagging of 36 but not 100 arginine-rich DPRs with mCherry increased toxicity, whereas adding mCherry or GFP to GA100 completely abolished toxicity. FLAG tagging also reduced GA100 toxicity but less than the longer fluorescent tags. Expression of untagged but not GFP- or mCherry-tagged GA100 caused DNA damage and increased p62 levels. Fluorescent tags also affected GA100 stability and degradation. In summary, protein tags affect DPR toxicity in a tag- and DPR-dependent manner, and GA toxicity might be underestimated in studies using tagged GA proteins. Thus, including untagged DPRs as controls is important when assessing DPR toxicity in preclinical models.

Assisted human reproduction legislation: Listening to the voice of patients

OBJECTIVE

Legislation and policies regarding assisted human reproduction (AHR) vary widely across nations and societies. As one of only 5 European countries which currently lacks legislation, Ireland now has a unique opportunity to learn from other jurisdictions and introduce AHR law that is reflective of the ongoing myriad developments in this complex field. Draft legislation, initially published in 2017, was revised in 2022 with strong political commitment to enacting in the same year. This study sought to ascertain the views of fertility patients (service users) to the proposed AHR legislation in its current format, prior to its implementation.

STUDY DESIGN

A survey questionnaire, previously designed to investigate the attitudes and perceptions of healthcare professionals (HCPs) towards a broad range of issues contained within the draft AHR Bill, was adapted for a patient/service user population. The survey link was distributed via secure email to all patients that had a doctor consult at our fertility clinic in 2020-2021.

RESULTS

The survey link was sent to 4420 patients/service users, of whom 1044 (23.6%) responded. A majority had experienced AHR treatment. Service users indicated strong support for AHR regulation and for access to all AHR techniques for all patients, irrespective of relationship or gender status. A majority of respondents disagreed with aspects of the draft bill regarding mandatory counselling, the timing of assignment of parentage in surrogacy, the exclusion of international surrogacy and the exclusion of men from posthumous AHR. Interestingly, the fertility patient cohort were more liberal in their views and opinions regarding AHR than the Irish HCPs previously surveyed.

CONCLUSION

This study demonstrates the views of a large group of AHR patients/service users towards proposed AHR legislation. Many of their views concur with but others differ from those of the drafters of the legislation and from those of healthcare professionals. Consideration of the views of all these groups and a collaborative approach would help ensure that Ireland has AHR legislation that is inclusive and fit for purpose in the 21st century.

Assisted human reproduction legislation: Acknowledging the voice of health care professionals

OBJECTIVE

Ireland is one of 5 European countries which currently lacks specific legislation on Assisted Human Reproduction (AHR). Draft legislation was introduced in 2017 and revised in 2022 with a view to enacting legislation this year (2022). This study sought to ascertain the views of healthcare professionals to proposed AHR legislation, prior to the implementation of that legislation.

STUDY DESIGN

A survey questionnaire based on all clinically relevant aspects of the Irish draft AHR Bill 2017 was distributed to relevant healthcare professionals using an online platform.

RESULTS

Over 200 healthcare personnel indicated strong support for the availability of AHR techniques, access to treatment for all patient populations regardless of relationship or gender status, and appropriate legislation and regulation in the field. Views of respondents are at variance with several proposals surrounding surrogacy, with 84 % favouring a pre-birth order to assign parentage from birth, rather than the proposed birth order 6 weeks after birth. The majority also support legislation around international surrogacy. Contrary to the draft Bill, respondents believe that men, as well as women, should be able to use posthumously any stored gametes or embryos belonging to the deceased partner or the couple. While the majority favour altruistic gamete donation, respondents support more generous compensation for donors, such as compensation for time lost at work.

CONCLUSION

This study has uniquely ascertained the views of healthcare professionals to imminent AHR legislation. It is hoped that the results will help inform the national legislation as it nears completion. Similar studies could help other countries, and policy bodies such as ESHRE to frame good legislation in this extremely specialised and complex field.

Comparison of neuropsychiatric side effects in an observational cohort of efavirenz- and protease inhibitor-treated patients

PURPOSE

To compare the extent of neuropsychiatric disturbances in two similar groups of HIV-infected patients treated for >4 weeks with either efavirenz (EFV) or protease inhibitors (PIs) as part of their antiretroviral therapy (ART).

METHOD

A cross-sectional, questionnaire-based cohort of HIV patients who received two nucleoside reverse transcriptase inhibitors combined with either EFV (n = 75) or one or more PIs (n = 77) for at least 4 weeks and were tolerating therapy. The extent of neuropsychiatric disturbances was evaluated based on self-reported symptoms using the psychological evaluation test SCL-90-R. Treatment duration was broken down into quartiles of 30-198 days, >198-365 days, >365-637 days, and >637 days.

RESULTS

In the first 6 months of therapy, significantly higher (worse) scores were seen in 39/75 (52%) of the patients receiving EFV. The EFV-treated group had significantly higher scores for somatization, anxiety, obsessive-compulsive behavior, the Global Severity Index, and the Positive Symptom Distress Index, with trends for higher scores in paranoid ideation and depression symptom subcategories. Over the following 6 to 12 months of therapy, the EFV group scored higher than the PI group in somatization, anxiety, obsessive-compulsive behavior, hostility, depression, the Global Severity Index, and the Positive Symptom Total, but the differences were not significant. After 12 months of therapy, the EFV group had significantly lower scores than the PI group for somatization, interpersonal sensitivity, Global Severity Index, and Positive Symptom Total.

CONCLUSION

EFV-induced neuropsychiatric symptoms can last up to 200 days after treatment initiation. However, symptom severity appears to decline over time in EFV-treated patients versus patients treated with a PI-based ART.