Biology subjects

Blank-Stein, N.

Publications and source records attributed to Blank-Stein, N..

3 recordsLinked to original sources

bioRxiv2025

Kupffer cells control neonatal hepatic metabolism via Igf1 signaling

During perinatal development, liver metabolism is tightly regulated to ensure energy supply for the newborn. Before birth, glycogen is stored in hepatocytes and later metabolized to glucose, meeting the energy demands of the neonate. Shortly after birth, lipogenesis begins, driven by the transcriptional activation of enzymes involved in fatty acid oxidation. These processes are thought to be largely regulated by systemic insulin and glucagon levels. However, the role of liver-derived local factors in neonatal hepatocyte metabolism remains unexplored. Kupffer cells (KCs), the livers resident macrophages, colonize the fetal liver early in embryogenesis and support liver metabolism in adulthood. Yet, whether KCs influence neonatal hepatocyte metabolism is unknown. Here, using conditional knockout mouse models targeting macrophages, we demonstrate that yolk sac-derived KCs play a critical role in hepatocyte glycogen storage and function by regulating the tricarboxylic acid (TCA) cycle - a role that monocyte-derived KC-like cells cannot substitute. Newborn pups lacking yolk sac-derived KCs mobilize glycogen more rapidly, a process regulated by insulin-like growth factor 1 (Igf1) production. Our findings reveal that macrophages are a major source of Igf1 at birth and that local Igf1 production by KCs is essential for balanced hepatocyte metabolism.

developmental biology↗

bioRxiv2024

Disease-associated microglia and activation of CD8+ T cells precede neuronal cell loss in a model of hereditary spastic paraplegia

In central nervous system (CNS) diseases characterized by late-onset neurodegeneration, the interplay between innate and adaptive immune responses remains poorly understood. This knowledge gap is amplified by the prolonged nature of these diseases, complicating the delineation of brain-resident and infiltrating cells. Here, we conducted a comprehensive profiling of innate and adaptive immune cells across various CNS regions in a murine model of spastic paraplegia 15 (SPG15), a complicated form of hereditary spastic paraplegia (HSP). Using fate-mapping of bone marrow-derived cells via genetic labeling, we identified microgliosis and microglial MHC-II upregulation accompanied by infiltration and local expansion of T cells in the CNS of Spg15-/- mice. Single-cell analysis revealed an increase of disease-associated microglia (DAM) and clonal expansion of effector CD8+ T cells across CNS regions occurring prior to neuronal loss. Analysis of potential cell-cell communication pathways suggested bidirectional interactions between DAM and effector CD8+ T cells potentially contributing to disease progression in Spg15-/- mice. In summary, we identified a shift in microglial phenotypes associated with recruitment and clonal expansion of T cells as a new characteristic of Spg15-driven neuropathology. Targeting activated microglia, CD8+ T cells and their communication represent promising avenues to prevent the loss of neuronal function in HSP.

immunology↗

bioRxiv2024

BBSome-dependent ciliary Hedgehog signaling governs cell fate in the white adipose tissue

The primary cilium has emerged as critical in regulating whole-body energy metabolism, as reflected in the Bardet-Biedl syndrome (BBS), where primary cilia dysfunction leads to obesity due to hyperphagia and white adipose tissue (WAT) remodeling. The regulation of cell fate and differentiation of adipocyte precursor cells (APCs) is key to maintaining WAT homeostasis during obesity. Using mice that recapitulated the BBS patient phenotype (Bbs8-/-), we demonstrate that primary cilia dysfunction reduces the stem-cell-like P1 APC subpopulation by inducing a phenotypic switch into a fibrogenic progenitor state, characterized by extracellular matrix (ECM) remodeling and upregulation of CD9. Single-cell RNA sequencing revealed a direct transition of stem-cell-like P1 cells into fibrogenic progenitors, bypassing the committed P2 cells. Ectopic ciliary Hedgehog signaling upon loss of BBS8 emerged as a central driver of the molecular changes in Bbs8-/- APCs, altering differentiation into adipocytes and lipid uptake. These findings unravel a novel role for primary cilia in governing APC fate, determining the delicate balance between adipogenesis and fibrogenesis. The identified molecular mechanisms provide insights into potential therapeutic targets for obesity.

cell biology↗