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Concise verdict

The Nature Communications paper reports that YAP is markedly upregulated in the pancreas of autoantibody positive and T1D donors and that YAP promotes coxsackievirus B (CVB) replication, inflammation, and beta cell apoptosis while inducing MST1 as a TEAD dependent negative feedback brake; YAP inhibition reduced viral replication in cells and ex vivo islet models and beta cell YAP overexpression in mice impaired glucose homeostasis and increased dedifferentiation (human donor n per group: control 13 AAb+ 15 T1D 15) YAP boosts enterovirus replication paper

Detailed critical review and analysis

1) What the paper did and main claims

• Reported increased YAP protein and Yap1 mRNA in exocrine pancreas and a small intraislet population in AAb+ and T1D organ donors vs controls (donor groups control n=13, AAb+ n=15, T1D n=15) and increased CTGF, a canonical YAP target, consistent with transcriptional YAP activity YAP expression and quantitation in donors
• Found YAP colocalization with enteroviral RNA in pancreas sections and that YAP overexpression increases CVB replication (RNA and VP1 protein) and apoptosis in β-cell lines and human islets; conversely YAP inhibition (verteporfin TEAD inhibitor and other loss-of-function approaches) reduced replication and inflammation in ex vivo systems Functional effects of YAP on CVB replication
• Mechanistic claim: YAP acts via TEAD to transcriptionally induce STK4/MST1 (ChIP qPCR and luciferase reporter evidence), generating a negative feedback loop in which MST1 limits excessive YAP-driven viral amplification; MST1 knockdown increased replication and decreased YAP-driven apoptosis in cell models YAP TEAD induces MST1 negative feedback
• In vivo: beta cell specific inducible YAP overexpression mice showed impaired glucose tolerance, reduced insulin secretion and beta cell dedifferentiation, supporting physiological relevance of YAP activation in islet dysfunction In vivo YAP overexpression consequences

2) Strengths

• Human pathology plus mechanistic work: integrates human nPOD tissues, RNAscope, single cell re-analyses, ex vivo human islet/exocrine co-cultures, cell lines and transgenic mice — convergent multi-model evidence increases causal inference (human data supported by mechanistic perturbations) Multi model integration in study
• Mechanistic depth: ChIP, luciferase reporters, TEAD inhibitor and S94A YAP mutant demonstrate YAP/TEAD direct regulation of STK4 (MST1) — supports a plausible negative feedback circuit rather than a purely correlative association YAP TEAD ChIP luciferase evidence
• Open code and data links: GitHub repository and Zenodo archive for reproducibility notebooks for scRNA and bulk analyses are provided (code available) which increases transparency YAP T1D code Zenodo

3) Limitations and potential weaknesses

1. Human sample size and heterogeneity — while the donor numbers are respectable for nPOD tissue work (controls 13, AAb+ 15, T1D 15), cross-sectional FFPE measures and per-donor scoring can be influenced by sampling location, duration of disease, post-mortem interval, and prior infections; causality therefore relies on models rather than the human tissue alone Limitations in donor sampling
2. Viral detection vs infectious virus — much of the human association relies on RNAscope for viral RNA; viral RNA may persist without productive infection and thus colocalization could reflect remnant RNA rather than active replication; paper partially addresses this with cell-based infectious readouts but more plaque assays from donor-derived material would strengthen claims Caveat viral RNA detection
3. Species and model differences — INS-1E (rat), PANC-1, HeLa, and mouse models were used; the Hippo network wiring and immune signalling differ between species and cell types (e.g., innate sensors, autophagy, proteostasis), so translatability of specific mechanistic links (e.g., magnitude of YAP effect on viral replication) to human in vivo disease requires caution Model species heterogeneity
4. Potential confounders in interpretation of IFN responses — YAP has previously been reported to both suppress and modulate type I IFN signalling in different contexts; here YAP overexpression increased expression of innate immunity/IFN genes in some models which may reflect complex dynamics where YAP enables viral replication and also drives an enhanced, potentially deleterious IFN response — disentangling direct proviral mechanisms from secondary immune activation needs careful time-resolved analyses YAP and IFN complexity
5. Therapeutic implications premature — authors suggest YAP as a potential antiviral target; however systemic targeting of Hippo/YAP has wide tissue effects (regeneration, cancer risk); specific targeting strategies, dosing windows and safety margins are not addressed and require rigorous preclinical toxicology given YAP roles in tissue repair and oncogenesis (multiple reviews show YAP importance across tissues) YAP as potential antiviral target and caveats

4) Data quality, reproducibility and availability

The authors provide source data files and link analysis code and notebooks on GitHub and Zenodo which materially improves reproducibility; the Zenodo DOI for the archived code is provided and the GitHub contains scRNA and bulk RNA notebooks for their analyses YAP T1D code Zenodo

5) How convincing is the causal claim that YAP drives enteroviral amplification and beta cell injury?

• Evidence in favor: Human co-localization data + in vitro gain/loss experiments (overexpression increases infectious readouts, inhibition reduces them) + ChIP/luciferase mechanistic links and murine phenotypes provide a strong multi-pronged case that YAP activity can promote productive CVB replication and islet dysfunction under experimental conditions Evidence for causality summary
• Remaining gaps: Temporal ordering in humans (did viral infection trigger YAP or vice versa) remains unresolved by cross-sectional tissue; whether YAP-mediated increases in replication are necessary in natural human infections (versus one of several host-permissive states) is not definitively proven; direct measurement of infectious virus in human tissues (e.g., culture/isolation) would strengthen translational claims.

6) Specific recommendations and follow-up experiments

1. From human tissues: attempt virus isolation/plaque assays or infectivity assays from fresh donor exocrine fragments where possible to demonstrate infectious virus associated with YAP positive cells rather than RNA fragments.
2. Time-resolved infections in primary human islets/exocrine co-cultures with simultaneous measurement of nuclear YAP, phospho-YAP, viral replication kinetics (PFU), and IFN/ISG induction to map causal temporal order (does YAP upregulation precede peak replication or follow it?).
3. Knock-in/knock-out experiments using CRISPRi/a in human islets to lower or raise endogenous YAP (rather than overexpression of constitutively active forms) to test physiological effect sizes and avoid artefacts of supra-physiological expression.
4. Pharmacology: test more selective TEAD inhibitors (and dose ranges) versus verteporfin, with careful off-target and toxicity profiling in pancreatic organoids and other tissues to evaluate therapeutic windows.
5. Population-level genetics and expression studies: examine whether human YAP pathway genetic variants or expression quantitative trait loci correlate with enteroviral susceptibility or T1D progression in cohorts with viral exposure data.

7) Overall balanced conclusion and confidence

Overall, this is a high-quality, mechanistically rich paper that makes a plausible and well-supported case that YAP activity can enhance enterovirus replication and exacerbate islet inflammation and beta cell injury, supported by human pathology, molecular mechanism, and animal phenotypes; however, the cross-sectional human data cannot alone prove directionality and translation to clinical therapeutics requires caution because of Hippo pathway pleiotropy and tissue-wide roles Overall study synthesis

8) Useful resources and quick links

• Full paper DOI 10.1038/s41467-025-64508-6 (opens in new tab)
• Analysis notebooks on GitHub
• Zenodo archive of YAP_T1D code

9) What would disprove the central model

Failing to reduce infectious CVB titers upon robust endogenous YAP knockdown in primary human islets, or replication of the human colocalization using infectious virus isolation rather than RNA, or demonstration that MST1 modulation has no effect on infectious virus in independent models would all substantially weaken the proposed model.

10) Quick practical takeaways for researchers

• Re-analyze the public scRNA datasets using the provided notebooks to confirm which pancreatic cell subtypes show YAP transcriptional signatures and CTGF co-expression (code available on GitHub/Zenodo) YAP code archive
• Design experiments that compare verteporfin to newer TEAD inhibitors and to genetic perturbations to understand on-target vs off-target effects on viral replication and beta cell survival.