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Biology subjects

Mikolaj, M.

Publications and source records attributed to Mikolaj, M..

3 recordsLinked to original sources

Hepatobiliary Progenitor-like Reprogramming in Liver Metastases

Metastatic progression requires cancer cells to adapt to the unique constraints of distant organ microenvironments, yet the mechanisms that drive organ-specific adaptations remain poorly understood. Here, we show that the liver actively rewrites metastatic cancer cell identity, driving tumor cells toward a hepatobiliary progenitor-like state. Through integrated transcriptomic, proteomic, metabolomic, and epigenomic analyses of patient-derived rapid-autopsy samples and experimental models, we identify this state as selectively enriched in liver metastases. It is characterized by co-activation of hepatic and biliary/progenitor regulators HNF4A and SOX9 and is observed across multiple epithelial cancers, indicating a conserved response to the hepatic niche. Mechanistically, hepatocyte-derived TGF-{beta} and hypoxia converge to activate a HIF-1-ACLY axis, increasing nuclear acetyl-coenzyme A availability and histone acetylation at hepatic lineage regulatory elements to drive hepatobiliary reprogramming. This coordinated niche-response program can be captured transcriptionally and is associated with inferior overall survival. Disruption of this pathway suppresses hepatic reprogramming and impairs liver metastatic fitness. These findings identify the liver as an active determinant of metastatic cell fate, linking microenvironmental signaling to metabolic and chromatin remodeling programs that enable lineage plasticity. More broadly, they reveal organ-specific reprogramming as a fundamental principle of metastasis and a therapeutic vulnerability in liver metastases.

cancer biology↗

Intravital single-molecule imaging reveals cytoskeletal turnover as a driver of membrane remodeling in live animals

Understanding how cells regulate plasma membrane architecture inside intact living organs in a live animal has been limited by the inability to directly measure molecular dynamics in vivo. Here we introduce intravital single-molecule microscopy (iSiMM), an imaging approach that enables tracking of individual, endogenously expressed cytoskeletal components at the plasma membrane in live mice. Applying iSiMM to murine acinar secretory cells, we identify discrete basolateral membrane domains built on deeply folded membrane infolds that function as a pre-existing membrane reservoir. Single-molecule measurements reveal continuous, regulated molecular turnover within these domains. Physiological stimulation accelerates cytoskeletal exchange promoting rapid membrane unfolding and cell expansion. Together, these findings establish iSiMM as a general strategy for probing molecular kinetics underlying dynamic cellular behaviors in intact organs. One-sentence summaryIntravital single-molecule microscopy enables direct measurement of molecular kinetics underlying dynamic cellular behaviors in intact living organs.

cell biology↗

Functionally Essential and Structurally Diverse: Insights into the zebrafish Left-Right Organizers Cilia via Optogenetic IFT88 Perturbation and Volume Electron Microscopy

In the zebrafish left-right organizer (LRO), the Kupffers Vesicle (KV), cilia extend from all cells into the fluid-filled lumen, but their structural diversity and contribution to morphogenesis remain incompletely defined. We hypothesized that cilia are required for KV development and may exist in distinct structural subtypes. Using a newly engineered transgenic line (sox17:Cry2-GFP), we optogenetically disrupted the intraflagellar transport protein IFT88 in KV progenitors via blue light-induced clustering of CIB1-RFP-IFT88. This perturbation impaired ciliogenesis and disrupted lumen formation, supporting a critical role for cilia in KV morphogenesis. To assess ciliary architecture, we used volume electron microscopy (vEM) to generate a high-resolution 3D ultrastructural map of mature KVs. Only 70.1% of cilia retained both mother and daughter centrioles, suggesting centriole elimination may occur in this tissue. Among centrioles present, 33.9% had distal appendages, 91.8% had subdistal appendages, and only 5.08% exhibited rootlet fibers. Cilia were also associated with membrane-bound vesicles, including spatially biased ciliary-associated vesicles (CaVs) and dense vesicles (CaDVs). These findings demonstrate that KV cilia are structurally diverse and spatially patterned, revealing a previously unappreciated level of complexity in LRO organization and providing new insight into how ciliary specialization may contribute to left-right axis specification.

developmental biology↗