Review Papers Claim by Claim

H1. Compensation by other mechanosensitive channels (subset-specific)

• The paper argues remaining RA/MA currents require non-PIEZO2 molecular mechanisms and that the fast RA subset is partially PIEZO2-dependent, implying other mechanogated channels contribute to the RA-class current pool. Authors’ compensation/trajectory interpretation
• Context from related mechanotransduction channel work supports the plausibility that multiple mechanosensors can generate overlapping mechanogated phenotypes in DRG sensory neurons (even if PIEZO2 is important for certain modalities or receptor endings). PIEZO1 vs PIEZO2 structural-functional differences
• Additionally, other mechanotransduction candidates have been reported as necessary in vivo for touch receptor function (e.g., ELKIN1/TMEM87a), showing the mechanotransduction “space” is not PIEZO2-only. Network embedding of PIEZO2 mechanotransduction (contextual evidence) PIEZO channel contributions may be non-redundant

H2. Developmental trajectory effects from gene deletion

• The authors explicitly suggest that loss-of-function phenotypes could arise from secondary developmental effects that alter sensory neuron trajectories, rather than from immediate channel loss alone. Developmental trajectory as an alternative explanation
• This interpretation is consistent with prior mechanotransduction genetics where timing and conditionality can strongly affect the measured phenotypes (though the excerpt does not re-test timing in this study). PIEZO2 cell-type essentiality example (Merkel cells)

• Earlier work reported PIEZO2 as a major transducer for touch in mice and emphasized strong reductions in mechanotransduction phenotypes upon PIEZO2 loss in vivo. PIEZO2 essentiality in Merkel mechanotransduction
• In another canonical line of evidence, PIEZO2 has been described as the principal mechanotransduction channel for proprioception. PIEZO2 principal role in proprioception
• This preprint’s novelty is that it finds no substantial reduction in mechanosensitive current incidence/sensitivity in cultured DRG neurons lacking PIEZO2, but does see a moderate reduction in the fastest RA subset and slower kinetics. Main contradiction resolution: subset-specific change rather than abolition

Strengths (based on provided excerpt)

• Two independent genetic strategies (constitutive KO and conditional KO) targeting PIEZO2 in sensory neurons, which reduces the probability that a single model artifact explains results. Two-model design reduces single-line artifacts
• Direct mechanical stimulation quantification using pillar deflection measurement with Gaussian fit approach, and explicit current classification by inactivation time constants into RA/IA/SA classes. Methods: pillar displacement & RA/IA/SA kinetics classification
• Verification of deletion in the conditional line via nearly absent PIEZO2 mRNA in lumbar DRG (smFISH/in situ quantification), supporting that the conditional allele functions in the sampled tissue. Conditional deletion verification via mRNA loss

Weak spots / missing information (limits interpretability)

• No molecular identification of the channels underlying the remaining mechanosensitive currents in Piezo2−/− or Piezo2cKO neurons; thus “compensation by other channels” is currently inference, not direct evidence. Residual-current attribution remains unspecified in excerpt
• In vitro versus in vivo translation: cultured DRG neurons on pillar arrays may not fully replicate the mechanotransduction microenvironment at sensory endings (ECM, Schwann cells, receptor complexes, tension regime). The paper discusses this issue conceptually (e.g., sensory Schwann cells and developmental/dependency complexity). Native context and cell-type dependence acknowledged by authors
• RA classification thresholds: currents are binned by τ_inact cutoffs; if genotype deletion shifts kinetics broadly, some currents may reclassify between RA/IA/SA without a true “incidence of RA channels” changing. This is a key alternative interpretation to test with single-channel or pharmacological dissection. Kinetic-class reclassification risk given genotype-dependent kinetics

• Show that residual mechanogated currents require non-PIEZO2 channels: e.g., pharmacological or genetic blockade of additional candidate mechanosensors would need to abolish the remaining incidence/amplitude (not merely shift kinetics). This follows logically from the authors’ claim that remaining currents are PIEZO2-independent. Falsifier logic implied by authors’ PIEZO2-independent inference
• Test timing/development causality: inducible or time-controlled PIEZO2 deletion would need to reproduce the same “incidence preserved, RA fraction reduced” profile without developmental compensation. The paper suggests developmental trajectory effects may contribute, so switching deletion timing is a critical falsifier. Developmental-trajectory falsifier: time-controlled deletion
• Ensure stimulus equivalence across methods: since earlier mechanosensitive current claims used indentation approaches, showing that pillar-vs-indentation differences do not underlie genotype-dependent outcomes would reduce methodological confounding. The paper discusses that both methods are efficient for PIEZO channels and that similar mechanosensitive currents are found in sensory neurons with both methods, but direct within-study cross-validation would be stronger. Methodological confound addressed but not fully controlled in excerpt