Biology subjects

Ikegami, S.

Publications and source records attributed to Ikegami, S..

3 recordsLinked to original sources

bioRxiv2026

A practical pipeline for volume rendering of trillion-voxel tomographic data

Recent advancements in tomography produce imaging data of geological materials (rocks and fossils) at trillion-voxel scales with multi-channels. Such high-resolution datasets are potentially keys to unveil evolutionary biological information with various shapes and sizes that have not been ever discovered. Volume rendering is an ideal visualization approach for them because it treats all voxels without relying on user-defined surface boundaries. However, these large-scale real-world tomographic data have rarely been volume-rendered at their native resolution, limiting the examination of rich morphological information. Here, we demonstrate a de facto standard volume-rendering pipeline running on a graphical processing unit (GPU)-equipped supercomputing system toward multi-channel, trillion-voxel tomographic data. Our workflow preserves original resolution, capturing detailed morphological information spanning microscopic to macroscopic scales. Systematic comparison of node types shows that GPU memory, rather than host memory, is the primary bottleneck. Our results establish a baseline for large-scale, multi-channel volume rendering of real tomographic data and demonstrate its applicability to geological samples. This work is presented as a practical demonstration of large-scale volume visualization.

paleontology↗

bioRxiv2026

Digest before Ingest: Early Recruitment of Membrane-bound DNaseX to Phagocytic Cups in Macrophages

Macrophages engulf and degrade pathogens and cellular debris through phagocytosis. The degradation process was generally believed to occur only after phagosome internalization and maturation. Here, we report an early DNase activity at the nascent phagocytic cup (PC) prior to its closure. Using a fluorescent DNase sensor, we revealed rapid and ubiquitous DNase activity upon PC formation across various macrophage types. We further identified the responsible enzyme as the membrane-bound DNaseX, which is constitutively recruited to the PC during PC formation. F-actin polymerization was found to correlate with DNase activity in the PC, likely by promoting physical engagement of DNaseX with solid DNA materials. Functionally, we show that macrophages degrade extracellular DNA (eDNA) within bacterial biofilms through direct physical contact, clearing the eDNA structures without internalization. These findings reveal a previously unrecognized DNA degradation mechanism operating at the macrophage membrane, suitable for degrading bulky eDNA materials which cannot be directly internalized by macrophages.

cell biology↗

bioRxiv2023

The cGAS-STING pathway is dispensable in a mouse model of LMNA-cardiomyopathy despite nuclear envelope rupture

Nuclear envelope (NE) ruptures are emerging observations in Lamin-related dilated cardiomyopathy, an adult-onset disease caused by loss-of-function mutations in Lamin A/C, a nuclear lamina component. Here, we tested a prevailing hypothesis that NE ruptures trigger pathological cGAS-STING cytosolic DNA-sensing pathway, using a mouse model of Lamin-cardiomyopathy. Reduction of Lamin A/C in cardiomyocytes of adult mice caused pervasive NE ruptures in cardiomyocytes, preceding inflammatory transcription, fibrosis, and fatal dilated cardiomyopathy. NE ruptures were followed by DNA damage accumulation without causing immediate cardiomyocyte death. However, cGAS-STING-dependent inflammatory signaling remained inactive. Deleting cGas or Sting did not rescue cardiomyopathy. The lack of cGAS-STING activation was likely due to the near absence of cGAS expression in adult cardiomyocytes at baseline. Instead, extracellular matrix (ECM) signaling was activated and predicted to initiate pro-inflammatory communication from Lamin-reduced cardiomyocytes to fibroblasts. Our work nominates ECM signaling, not cGAS-STING, as a potential inflammatory contributor in Lamin-cardiomyopathy.

molecular biology↗