Ali T et al., JCI Insight - Um antirretroviral aprovado para HIV, dado por via oral em microdose, prolongou a sobrevida de camundongos que carregam a proteína priônica humana e foram infectados com príons de doença de Creutzfeldt-Jakob esporádica humana. O efavirenz age ativando a CYP46A1, a enzima cerebral que converte colesterol numa forma capaz de sair do cérebro — e não baixando a proteína priônica, como as abordagens dos episódios anteriores desta série. Termos-chave: efavirenz, CYP46A1, doença de Creutzfeldt-Jakob, metabolismo do colesterol cerebral, reposicionamento de medicamento.

⚠️ Importante: nada neste episódio é motivo para tomar efavirenz.
O efavirenz é um antirretroviral de prescrição com efeitos colaterais reais, incluindo distúrbio do sono, sonhos vívidos, tontura e efeitos psiquiátricos. A dose usada neste estudo — cerca de 0,09 mg/kg por dia — é algo entre 300 e 400 vezes menor que a dose prescrita para HIV, e não é algo que alguém consiga aproximar por conta própria. Nenhum ser humano teve benefício demonstrado com efavirenz para doença priônica. Existe um ensaio de Fase 3 registrado como NCT07482085 no ClinicalTrials.gov, que ainda não reportou resultados. Se a doença priônica afeta você ou sua família, converse com um neurologista e pergunte sobre ensaios registrados — não sobre a farmácia.
Este é o quarto episódio da nossa série sobre a doença de Creutzfeldt-Jakob, que começou como homenagem ao Lito Sousa. Todos os ensaios citados na série estão registrados publicamente no ClinicalTrials.gov.

Destaques do estudo:
Os autores inocularam camundongos tg650, que superexpressam a PrP humana, com príons MM1 de CJD esporádica humana e começaram o efavirenz oral em dose baixa aos 30 ou aos 130 dias após a infecção, prolongando a sobrevida em 17 e 23 dias respectivamente. Na fase clínica inicial, os animais tratados apresentaram menos PrPSc, menor teor de colesterol e de gotículas lipídicas no cérebro, e níveis mais altos de CYP46A1 e de 24S-hidroxicolesterol no cérebro e no soro. Superexpressar a CYP46A1 sozinha em células neuronais infectadas já reduziu a PrPSc e elevou o 24S-hidroxicolesterol, ligando o efeito antipriônico à enzima e não a outra propriedade do remédio. A dose usada foi de cerca de 0,09 mg/kg por dia, algo entre 300 e 400 vezes menor que a dose padrão prescrita para HIV. A eficácia no início tardio importa clinicamente, porque o paciente chega depois que os sintomas começaram.

Conclusão:
O efavirenz oral em dose baixa ativa a CYP46A1, restaura a renovação de colesterol no cérebro, reduz o acúmulo de PrPSc e prolonga a sobrevida num modelo humanizado de CJD esporádica, o que sustenta avaliar melhor esse medicamento reposicionado em doença priônica humana.

Música:
Ouça a música criada a partir deste artigo no final do episódio.

Título do artigo:
Treatment with efavirenz extends survival in a Creutzfeldt-Jakob disease model by regulating brain cholesterol metabolism

Primeiro autor:
Ali T

Revista:
JCI Insight

DOI:
10.1172/jci.insight.190296

Referência:
Ali T, Cashion J, Hannaoui S, Ahmed-Hassan H, Schatzl H, Gilch S. Treatment with efavirenz extends survival in a Creutzfeldt-Jakob disease model by regulating brain cholesterol metabolism. JCI Insight. 2025;10(14):e190296. doi:10.1172/jci.insight.190296

Licença:
Este episódio é baseado em um artigo de acesso aberto publicado sob a Licença Creative Commons Atribuição 4.0 Internacional (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

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Ali T et al., JCI Insight - Repurposed low-dose efavirenz slowed disease progression and extended survival in tg650 mice inoculated with MM1 sCJD prions by activating CYP46A1, raising 24S‑hydroxycholesterol and reducing PrPSc, brain cholesterol and lipid droplets at the early clinical stage. Key terms: efavirenz, CYP46A1, Creutzfeldt-Jakob disease, cholesterol metabolism, prion disease.

⚠️ Important: nothing in this episode is a reason to take efavirenz.
Efavirenz is a prescription antiretroviral with real side effects, including sleep disturbance, vivid dreams, dizziness and psychiatric effects. The dose used in this study — about 0.09 mg/kg per day — is roughly 300 to 400 times lower than the dose prescribed for HIV, and is not something anyone can approximate on their own. No human being has yet been shown to benefit from efavirenz for prion disease. A Phase 3 trial is registered as NCT07482085 on ClinicalTrials.gov and has not reported results. If prion disease affects you or your family, talk to a neurologist and ask about registered trials — not about a pharmacy.
This episode is the fourth in our series on Creutzfeldt-Jakob disease, which began as a dedication to Lito Sousa. Every trial named in the series is registered publicly on ClinicalTrials.gov.

Study Highlights:
Oral low-dose efavirenz given to human-PrP–overexpressing tg650 mice starting at 30 or 130 days postinoculation significantly slowed clinical progression and extended survival by 17 and 23 days, respectively. At the early clinical stage EFV-treated mice showed reduced PK-resistant PrPSc, decreased brain cholesterol and lipid droplets, and increased CYP46A1 expression with higher 24S‑hydroxycholesterol in brain and serum. Overexpression of CYP46A1 in prion-infected neuronal cells likewise reduced PrPSc, supporting a causal link between CYP46A1 activation and antiprion effects.

Conclusion:
Low-dose oral efavirenz activates CYP46A1, restores cholesterol turnover, reduces early PrPSc accumulation and lipid pathology, and extends survival in a humanized sCJD mouse model, supporting EFV as a candidate for further evaluation in human prion disease.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Treatment with efavirenz extends survival in a Creutzfeldt-Jakob disease model by regulating brain cholesterol metabolism

First author:
Ali T

Journal:
JCI Insight

DOI:
10.1172/jci.insight.190296

Reference:
Ali T, Cashion J, Hannaoui S, Ahmed-Hassan H, Schatzl H, Gilch S. Treatment with efavirenz extends survival in a Creutzfeldt-Jakob disease model by regulating brain cholesterol metabolism. JCI Insight. 2025;10(14):e190296. https://doi.org/10.1172/jci.insight.190296.

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base is independent and ad-free — no sponsors, no paywall. If an episode was worth your time, chip in and keep the papers audited and the original songs coming:
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More at basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/efavirenz-prion-cjd-cholesterol

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-08-31.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript's core biomedical claims about EFV's e...

Minikel EV et al., Nucleic Acids Research - Este estudo testa a redução da proteína priônica (PrP) por oligonucleotídeos antisense (ASOs) em camundongos, variando doses, esquemas de aplicação, linhagens de príon e estágios da doença. O tratamento reduziu o RNA do Prnp, prolongou a sobrevida, atrasou os sintomas e reverteu biomarcadores de lesão neuronal e de gliose em vários cenários. O benefício apareceu mesmo com redução parcial, nas cinco linhagens testadas, e em alguns casos até depois do início dos sintomas. Termos-chave: proteína priônica, oligonucleotídeo antisense, neurodegeneração, biomarcadores, terapias.

Destaques do estudo:
A redução da PrP mediada por ASO prolongou a sobrevida e atrasou o início da doença tanto no esquema profilático quanto no tardio, em diferentes químicas de ASO. O benefício foi dose-dependente — uma redução de apenas cerca de 21 por cento do RNA já produziu ganho mensurável de sobrevida — e apareceu contra cinco linhagens distintas de príon adaptadas a camundongo, sem sinal de linhagens resistentes ao tratamento. Uma dose única aplicada depois da detecção da patologia reverteu a alta do neurofilamento leve no plasma e reduziu a bioluminescência de GFAP; a supressão crônica iniciada até o começo da neuropatologia alcançou benefício comparável ao de camundongos com apenas uma cópia funcional do gene da PrP. Alguns animais tratados já com sintomas francos tiveram sobrevida prolongada, embora a tolerabilidade de certas químicas de ASO em fase tardia tenha sido limitada.

Conclusão:
Reduzir a PrP por ASO, via mecanismo dependente de RNase H, é uma estratégia modificadora de doença amplamente eficaz nos modelos de príon em camundongo — atravessando linhagens e estágios — e justifica o desenvolvimento de terapias que baixem a PrP, com esquemas de dose apropriados.

Música:
Ouça a música criada a partir deste artigo no final do episódio.

Título do artigo:
Prion protein lowering is a disease-modifying therapy across prion disease stages, strains and endpoints

Primeiro autor:
Minikel EV

Revista:
Nucleic Acids Research

DOI:
10.1093/nar/gkaa616

Referência:
Minikel EV, Zhao HT, Le J, O’Moore J, Pitstick R, Graffam S, Carlson GA, Kavanaugh MP, Kriz J, Kim JB, Ma J, Wille H, Aiken J, McKenzie D, Doh-ura K, Beck M, O’Keefe R, Stathopoulos J, Caron T, Schreiber SL, Carroll JB, Kordasiewicz HB, Cabin DE, Vallabh SM. Prion protein lowering is a disease-modifying therapy across prion disease stages, strains and endpoints. Nucleic Acids Research. 2020;48(19):10615–10631. doi:10.1093/nar/gkaa616

Licença:
Este episódio é baseado em um artigo de acesso aberto publicado sob a Licença Creative Commons Atribuição 4.0 Internacional (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Apoie:
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No PaperCast Base by Base você acompanha o que há de mais recente em genômica, genômica funcional, genômica estrutural e proteômica.

Link do episódio: https://basebybase.com/episodes/prion-protein-lowering-across-strains-pt

QC:
Este episódio foi conferido contra o PDF original do artigo e os metadados da publicação, para a edição publicada em 2026-08-28.

Escopo do QC:
- metadados do artigo e as afirmações científicas centrais da narração
- exclui analogias, abertura/encerramento e música
- cobertura da transcrição: Audited the transcript sections describing mechanism of action (RNase H–mediated PrP reduction), dose-response and minimal knockdown, cross-strain efficacy across five prion strains, treatmen...

Minikel EV et al., Nucleic Acids Research - This study uses antisense oligonucleotides (ASOs) to lower prion protein (PrP) RNA in mice and shows dose-dependent extension of survival, efficacy across multiple prion strains, reversal of molecular biomarkers, and benefit even when treatment is delayed into symptomatic stages. Key terms: prion protein, antisense oligonucleotide, neurodegeneration, biomarkers, survival.

Study Highlights:
Using ASOs to reduce PrP RNA in intracerebrally inoculated mice produced dose-dependent extension of survival in both prophylactic and delayed dosing paradigms. Less than 25% PrP suppression was sufficient to delay symptoms and extend survival. Treatment was effective across five distinct prion strains without evidence of drug-resistant prions. Biomarkers of neuronal injury (plasma NfL) and astrocytosis (GFAP bioluminescence) were reversed after ASO treatment, and chronic early dosing matched benefits seen in heterozygous PrP knockout animals.

Conclusion:
ASO-mediated PrP lowering is a robust, disease-modifying approach in mouse models of prion disease across strains and disease stages, supporting advancement of PrP-lowering therapeutics and use of CSF PrP and blood NfL as pharmacodynamic biomarkers.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Prion protein lowering is a disease-modifying therapy across prion disease stages, strains and endpoints

First author:
Minikel EV

Journal:
Nucleic Acids Research

DOI:
10.1093/nar/gkaa616

Reference:
Minikel EV, Zhao HT, Le J, O’Moore J, Pitstick R, Graffam S, Carlson GA, Kavanaugh MP, Kriz J, Kim JB, Ma J, Wille H, Aiken J, McKenzie D, Doh-ura K, Beck M, O’Keefe R, Stathopoulos J, Caron T, Schreiber SL, Carroll JB, Kordasiewicz HB, Cabin DE, Vallabh SM. Prion protein lowering is a disease-modifying therapy across prion disease stages, strains and endpoints. Nucleic Acids Research. 2020;48(19):10615–10631. doi:10.1093/nar/gkaa616

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base is independent and ad-free — no sponsors, no paywall. If an episode was worth your time, chip in and keep the papers audited and the original songs coming:
❤️ Support monthly: https://buy.stripe.com/cNifZhclVebvagk2JDgEg01
☕ One-time donation: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00
More at basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/prion-protein-lowering-stages-strains-endpoints

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-08-25.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited sections include PrP biology and PrP function; ASO mechanism and RNase H action; dose-response and minimal PrP knockdown; cross-strain efficacy across five mouse prion strains; biomarkers (plasma NfL and GFAP bioluminescence); therapeutic timing (prophylactic, early/delayed, late/symptomatic); resistance and tr
- transcript topics: Prion protein biology and PrP function; ASO mechanism and RNase H action; Dose-response and minimal PrP knockdown; Cross-strain efficacy across five mouse prion strains; Biomarkers: plasma neurofilament light (NfL) and GFAP bioluminescence; Behavioral readouts: rotarod and nest-building

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 5
- claims flagged for review: 0
- metadata check...

Raymond GJ et al., JCI Insight - This episode covers a 2019 study showing that sequence-specific antisense oligonucleotides (ASOs) targeting the prion protein (PrP) mRNA, delivered by bolus intracerebroventricular injection, lower PrP levels in the CNS, slow neuropathology, and markedly extend survival in prion-infected wild-type mice when given prophylactically or even near symptom onset. Key terms: antisense oligonucleotide, prion disease, prion protein, intracerebroventricular, mouse model.

Study Highlights:
Two PrP-targeting ASOs (active ASO 1 and 2) reduced Prnp mRNA and PrP protein across brain regions and produced robust survival benefits in RML prion–infected wild-type mice, with prophylactic extension of lifespan by 61%–98%. A single bolus dose given at 120 days post-infection (near clinical onset) extended survival by 55% and slowed symptomatic progression. A non‑targeting control ASO showed no efficacy, indicating a sequence-specific, on‑target mechanism mediated by RNase H–dependent RNA lowering. Some tolerability issues were observed with particular ASO candidates at late-stage treatment, but at least one active ASO was both tolerated and effective.

Conclusion:
Bolus CNS delivery of sequence-specific PrP‑lowering ASOs lowers PrP, delays prion neuropathology, and substantially extends survival in infected mice, supporting further development of PrP‑lowering therapy and use of CSF PrP as a pharmacodynamic biomarker.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Antisense oligonucleotides extend survival of prion-infected mice

First author:
Raymond GJ

Journal:
JCI Insight

DOI:
10.1172/jci.insight.131175

Reference:
Raymond GJ, Zhao HT, Race B, et al. Antisense oligonucleotides extend survival of prion-infected mice. JCI Insight. 2019;4(16):e131175. doi:10.1172/jci.insight.131175.

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base is independent and ad-free — no sponsors, no paywall. If an episode was worth your time, chip in and keep the papers audited and the original songs coming:
❤️ Support monthly: https://buy.stripe.com/cNifZhclVebvagk2JDgEg01
☕ One-time donation: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00
More at basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/450-prp-lowering-asos-prion-mice

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-08-24.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited sections describing ASOs targeting Prnp, PrP reduction, i.c.v. bolus delivery, prophylactic vs late-stage treatment in prion-infected mice, and the role of control ASOs and sequence specificity.
- transcript topics: Antisense oligonucleotides targeting Prnp mRNA; PrP reduction and PrP biology; Intracerebroventricular bolus delivery vs continuous infusion; Prophylactic vs late-stage treatment in prion-infected mice; Sequence specificity and non-targeting control ASO; Pharmacodynamic biomarker: CSF PrP measurement

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 6
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- ASOs targeting Prnp mRNA discussed as a therap...

Gentile JE et al., Nucleic Acids Research - Discovery and preclinical development of divalent siRNA candidates targeting PRNP, identifying 2439-s4 as a potent, durable human PRNP-lowering drug candidate with IND clearance. Key terms: prion disease, PrP lowering, divalent siRNA, 2439-s4, RNAi therapeutics.

Study Highlights:
Authors screened divalent siRNA libraries and identified mouse-targeting 1682-s4 that lowered brain PrP to ~49% and extended survival in prion-infected mice when dosed pre- or post-symptomatically. They generated human PRNP transgenic mouse lines (Tg25109, Tg26372) and nominated 2439-s4, which reduced whole-hemisphere human PrP to as low as 17% after a single dose. Mechanistic analysis showed that the s4 scaffold’s fixed 3' UU tail and exNA terminal linkages each contributed to superior potency and durability versus other scaffolds. GLP toxicology in rats and dogs found no significant adverse findings and the US FDA cleared an IND to advance 2439-s4 to clinical trials.

Conclusion:
Divalent siRNA 2439-s4 is a potent, durable PRNP-lowering candidate with favorable preclinical safety and regulatory clearance to proceed to clinical testing.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Divalent siRNA for prion disease

First author:
Gentile JE

Journal:
Nucleic Acids Research

DOI:
10.1093/nar/gkag287

Reference:
Gentile JE, Corridon TL, Serack FE, et al. Divalent siRNA for prion disease. Nucleic Acids Research. 2026;54:gkag287. doi:10.1093/nar/gkag287

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base is independent and ad-free — no sponsors, no paywall. If an episode was worth your time, chip in and keep the papers audited and the original songs coming:
❤️ Support monthly: https://buy.stripe.com/cNifZhclVebvagk2JDgEg01
☕ One-time donation: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00
More at basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/divalent-sirna-prion-disease

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-08-24.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited transcript sections covering PRNP biology, divalent siRNA mechanism (s4 scaffold with UU tail and exNA), lead sequences (1682-s4 and 2439-s4), human PRNP transgenic mice models, intrathecal delivery, RT-qPCR and ELISA readouts, PK/PD durability, prion-infected survival data, and IND status.
- transcript topics: Prion biology and PRNP as therapeutic target; Divalent siRNA mechanism and s4 scaffold features (UU tail, exNA); Lead sequences 1682-s4 and 2439-s4 and in vivo screening; Transgenic human PRNP mice Tg25109 and Tg26372; Intrathecal delivery and brain distribution; Analytical readouts: RT-qPCR and PrP ELISA

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 6
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- DOI canonical form 10.1093/nar/gkag287
- Article title: Divalent siRNA for prion disease
- Journal: Nucleic Acids Research
- License: Creative Commons Attribution 4.0 International License (CC BY 4.0)
- Lead sequences identified: 1682-s4 (mouse Prnp) and 2439-...

Raymond GJ et al., JCI Insight - This study tests antisense oligonucleotides (ASOs) targeting Prnp in wild‑type mice infected with RML prions and shows that sequence‑specific PrP lowering by bolus i.c.v. ASO dosing delays disease and extends survival, even when given near clinical onset. Key terms: prion disease, antisense oligonucleotide, PrP lowering, mouse model, intracerebroventricular delivery.

Study Highlights:
Two sequence‑specific ASOs targeting mouse Prnp lowered Prnp mRNA and PrP protein in brain and delayed neuropathology compared with a non‑targeting control. Prophylactic bolus i.c.v. dosing given every 2–3 months extended survival by 61%–98%. A single ASO dose at 120 days post‑infection, near expected symptom onset, extended survival by 55% and slowed symptomatic progression. Control ASO showed no benefit, supporting RNA‑lowering as the mechanism of action.

Conclusion:
Bolus intracerebroventricular delivery of PrP‑targeting ASOs lowers PrP via RNase H–mediated mRNA degradation, slows accumulation of misfolded PrP, and substantially extends survival in prion‑infected mice, including when treatment is initiated near clinical onset.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Antisense oligonucleotides extend survival of prion‑infected mice

First author:
Raymond GJ

Journal:
JCI Insight

DOI:
10.1172/jci.insight.131175

Reference:
Raymond GJ, Tran Zhao H, Race B, Raymond LD, Williams K, Swayze EE, Graffam S, Le J, Caron T, Stathopoulos J, O’Keefe R, Lubke LDL, Reidenbach AG, Kraus A, Schreiber SL, Mazur C, Cabin DE, Carroll JB, Minikel EV, Kordasiewicz H, Caughey B, Vallabh SM. Antisense oligonucleotides extend survival of prion‑infected mice. JCI Insight. 2019;4(16):e131175. https://doi.org/10.1172/jci.insight.131175.

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

Support:
Base by Base is independent and ad-free — no sponsors, no paywall. If an episode was worth your time, chip in and keep the papers audited and the original songs coming:
❤️ Support monthly: https://buy.stripe.com/cNifZhclVebvagk2JDgEg01
☕ One-time donation: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00
More at basebybase.com

On PaperCast Base by Base you'll discover the latest in genomics, functional genomics, structural genomics, and proteomics.

Episode link: https://basebybase.com/episodes/prp-lowering-asos-prolong-survival-ep448

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-08-23.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript sections describing PrP biology, ASO mechanism (RNA lowering vs aptameric), delivery strategy, prophylactic and late-stage efficacy, control experiments, neuropathology, and translational implications.
- transcript topics: Prion biology and PrP involvement; ASO mechanism: RNA lowering vs aptameric effects; Delivery methods: bolus i.c.v. vs osmotic pumps; Prophylactic ASO efficacy in mice (onset delay, survival extension); scrambled control ASO vs active ASOs; Late-stage (120 dpi) ASO efficacy and ASO2 toxicity

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 5
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- ASOs lowered Prnp mRNA and reduced PrP protein in brain regions
- Prophylactic ASO...

• (00:00:00) - The genetic silencing approach to Creutzfeldt-Jak
• (00:02:27) - What is Prion Disease?
• (00:06:16) - How to Turn off prion disease's spread
• (00:11:54) - AsO 1, the scrambled ASO
• (00:12:47) - ASO2 delays the RML prion progression by nearly three
• (00:17:14) - The neuroscience of prion disease
• (00:21:11) - Thanks for listening to Prion Disease Podcasts
• (00:22:35) - Silence the Spark

Gentile JE et al., Nucleic Acids Research - This study develops and tests divalent siRNA molecules that lower prion protein (PrP) in the brain, identifies a potent human-targeting candidate (2439-s4), demonstrates survival benefit in prion-infected mice with a mouse-targeting tool compound, and reports IND-enabling toxicology supporting clinical testing. Key terms: prion disease, PrP lowering, divalent siRNA, 2439-s4, transgenic mouse.

Study Highlights:
The authors identify a mouse Prnp-targeting divalent siRNA (1682-s4) that lowers brain PrP to ~49% residual and extends survival in RML prion–infected mice (2.7-fold when dosed presymptomatically, 64% increase after a single symptomatic dose). They generate two transgenic mouse lines expressing full human PRNP (Tg25109, Tg26372) and use them to discover human-targeting siRNA 2439, optimized as 2439-s4, which lowers whole-hemisphere human PrP to 17% residual at 348 μg and to 49% at 52 μg. Chemical features—an exNA terminal linkage and a fixed 3' UU tail—each contribute substantially to potency, and a single dose shows durability out to months while 1–2% of CSF dose is retained in brain. GLP toxicology in rats and dogs identified no major liabilities and the FDA cleared an IND to advance 2439-s4 to human trials.

Conclusion:
Divalent siRNA can achieve deep, durable PrP lowering in the CNS, confer disease-modifying benefit in a mouse prion model, and yield a clinical candidate (2439-s4) with supportive nonclinical toxicology and regulatory clearance for a first-in-human study.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Divalent siRNA for prion disease

First author:
Gentile JE

Journal:
Nucleic Acids Research

DOI:
10.1093/nar/gkag287

Reference:
Gentile JE, Corridon TL, Serack FE, Echeverria D, Kennedy ZC, et al. Divalent siRNA for prion disease. Nucleic Acids Research. 2026;54:gkag287. doi:10.1093/nar/gkag287

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

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Episode link: https://basebybase.com/episodes/divalent-sirna-prion-disease

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-08-23.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited sections covering: divalent siRNA mechanism and CNS delivery; mouse Prnp knockdown and survival data for 1682-s4; human PRNP targeting with 2439-s4 in transgenic mice; scaffold optimization (exNA, fixed tail, PS); PK/PD and IND-enabling GLP tox; and FDA IND clearance.
- transcript topics: Divalent siRNA mechanism and CNS delivery; Mouse Prnp knockdown and survival in prion model with 1682-s4; Human PRNP transgenic mouse models Tg25109/Tg26372 and lead candidate 2439-s4; Chemical scaffold optimization (PS reductions, exNA, fixed UU tail); IND-enabling GLP toxicology and FDA IND clearance; PK/PD metrics (IC50 ~1.2 μg/g; tissue retention 1–2% dose)

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 6
- claims flagged for review: 0
- metadata checks passed: 4
- metadata is...

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