Biology subjects

Venida, A.

Publications and source records attributed to Venida, A..

3 recordsLinked to original sources

bioRxiv2026

The MIRO1-BAX Complex Dictates Life and Death at the Mitochondrial Gate

BAX macropores in the outer mitochondrial membrane (OMM) are canonical mediators of apoptosis, but whether the same pore structure can drive distinct cell death pathways remains unclear. Here, we identify the OMM protein MIRO1 as a context-specific modulator of BAX activity. Mechanistically, MIRO1 binds BAX via MIRO1s N-terminal domain to promote macropore formation and the release of mitochondrial DNA (mtDNA) into the cytoplasm, triggering the STING-pIRF3 signaling axis. In glioma cells, this pathway sustains GPX4 expression via pIRF3-mediated transcriptional activation and confers ferroptosis resistance while bypassing inflammation. By contrast, in Parkinsonian neurons, the MIRO1-BAX complex promotes mitochondrial-stress-induced apoptosis. Using structure-guided drug discovery, we developed first-in-class small molecules that allosterically disrupt the MIRO1-BAX complex by engaging MIRO1s distal GTPase pocket. These compounds sensitize glioma cells to ferroptosis and protect neurons from apoptosis. Our findings reveal a disease-specific mitochondrial switch for life-death decisions and illuminate the molecular logic by which cells exploit and interpret OMM permeabilization.

Cell Biology↗

bioRxiv2025

Defined human tri-lineage brain microtissues

Microglia are the immune cells of the central nervous system and are thought to be key players in both physiological and disease conditions. Several microglial features are poorly conserved between mice and human, such as the function of the neurodegeneration-associated immune receptor Trem2. Induced pluripotent stem cell (iPSC)-derived microglia offer a powerful opportunity to generate and study human microglia. However, human iPSC-derived microglia often exhibit activated phenotypes in vitro, and assessing their impact on other brain cell types remains challenging due to limitations in current co-culture systems. Here, we developed fully defined brain microtissues, composed of human iPSC-derived neurons, astrocytes, and microglia, co-cultured in 2D or 3D formats. Our microtissues are stable and self-sufficient over time, requiring no exogenous cytokines or growth factors. All three cell types exhibit morphologies characteristic of their in vivo environment and show functional properties. Co-cultured microglia develop more homeostatic phenotypes compared to microglia exposed to exogenous cytokines. Hence, these tri-cultures provide a unique approach to investigate cell-cell interactions between brain cell types. We found that astrocytes and not neurons are sufficient for microglial survival and maturation, and that astrocyte-derived M-CSF is essential for microglial survival. Single-cell and single-nucleus RNA sequencing analyses nominated a network of reciprocal communication between cell types. Brain microtissues faithfully recapitulated pathogenic -synuclein seeding and aggregation, suggesting their usefulness as human cell models to study not only normal but also pathological cell biological processes.

neuroscience↗

bioRxiv2019

The Development, Function, and Plasticity of the Immune Macroenvironment in Cancer

Harnessing immune defense mechanisms has revolutionized cancer therapy, but our understanding of the factors governing immune responses in cancer remains incomplete, limiting patient benefit. Here, we use mass cytometry to define the organism-wide immune landscape in response to tumor development across five tissues in eight tumor models. Systemic immunity was dramatically altered across mouse models and cancer patients, with changes in peripheral tissues differing from those in the tumor microenvironment and taking place in phases during tumor growth. This tumor-experienced immune system mounted dampened responses to orthogonal challenges, including reduced T cell activation during viral or bacterial infection. Disruptions in T cell responses were not cell-intrinsic but rather due to reduced responses in antigen-presenting cells (APCs). Promoting APC activation was sufficient to restore T cell responses to orthogonal infection. All systemic immune changes were reversed with surgical tumor resection, revealing remarkable plasticity in the systemic immune state, which contrasts with terminal immune dysfunction in the tumor microenvironment. These results demonstrate that tumor development dynamically reshapes the composition and function of the immune macroenvironment.

immunology↗