VCLMU: Mechanism-Centric Virtual Cell World Modeling for Perturbation Response
Organizations: Johnson & Johnson Innovative Medicine · University of Texas at Arlington
Abstract
Predicting cellular responses to genetic perturbations is a central capability for virtual cells and a key step toward computational modeling of biological interventions. Most existing models directly map an unperturbed molecular profile and perturba- tion to the resulting observation without explicitly representing the latent cellular transition induced by the intervention. We introduce a mechanism-centric virtual cell world model that represents cellular state as a set of Latent Mechanism Units (LMUs) and treats genetic perturbations as actions on these latent states. Each LMU combines a reusable identity grounded in multimodal biological evidence with an observation-specific state, allowing a perturbation to induce mechanism- specific stochastic transitions before decoding the resulting transcriptional response. We train VCLMU through two-stage pretraining, first on around 200K pseudo-bulk perturbation profiles and then on gene-aligned single-cell perturbation data. Across six perturbation-disjoint benchmarks, VCLMU consistently improves perturbation- specific response recovery over strong baselines while maintaining competitive global response accuracy. We further analyze learned LMUs through enrichment between perturbation responses and LMU gene sets and show that they capture structured biological response programs. These results support mechanism-level latent state transition as a useful formulation for virtual cell models that aim to predict and interpret cellular responses to biological interventions.
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Appendix
| Symbol | Meaning |
|---|---|
| , | number of genes; gene index |
| , | number of LMUs in the bank; LMU index |
| , | number of active LMUs for sample ; their index set |
| , | candidate genes per LMU; candidate set of LMU |
| , | model width; latent transition width |
| , , | control profile; observed perturbed profile; predicted perturbed profile |
| Evidence | Source | Description | Dim. |
|---|---|---|---|
| Training co-expression | Principal components of the training-set gene–gene co-expression matrix, capturing major transcriptional covariance patterns. | ||
| Gene Ontology [ 35 ] | Gene–term association matrix compressed using truncated SVD to summarize biological process, molecular function, and cellular component annotations. | 512 | |
| MSigDB Hallmark [ 36 ] | Binary membership in the Hallmark gene sets, representing approximately 50 curated biological programs. | ||
| PROGENy [ 28 ] | Association with the 14 PROGENy signaling pathways, providing pathway-level functional information. | 14 | |
| Gene2Vec [ 37 ] | Pretrained gene embeddings capturing functional similarity learned from large-scale biological co-occurrence. | 200 | |
| STRING + Mashup [ 38 , 39 ] | Protein interaction network embedding capturing both local and global network topology. | 800 |
Single-Cell Perturbation Modeling
Single-cell perturbation modeling predicts how genetic or chemical interventions change cellular states across cells and contexts.
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