Biology subjects

Guldner, I.

Publications and source records attributed to Guldner, I..

3 recordsLinked to original sources

bioRxiv2024

Circulatory proteins shape microglia state and boost phagocytosis

Microglia, the brains immune cells, are highly responsive to their local environment. Given that circulatory proteins can enter the brain, we asked whether microglia are responsive to such proteins. Here, we identify a stable population of microglia specialized to take up circulatory proteins in a region-specific manner under physiological conditions; human hematopoietic stem cell-derived microglia replacing endogenous microglia in chimeric mice show similar regional specialization. Plasma-positive microglia are characterized by prominent expression of genes related to innate immunity and antigen presentation and exhibit high metabolic and phagocytic activity. This activity is dependent, in part, on microglial uptake and accumulation of circulatory Apolipoprotein AI (ApoA-I). Our findings thus identify a new model of communication between brain and periphery through specialized microglia.

neuroscience↗

bioRxiv2023

APOE4/4 is linked to damaging lipid droplets in Alzheimer's microglia

Several genetic risk factors for Alzheimers Disease (AD) implicate genes involved in lipid metabolism and many of these lipid genes are highly expressed in glial cells. However, the relationship between lipid metabolism in glia and AD pathology remains poorly understood. Through single-nucleus RNA-sequencing of AD brain tissue, we have identified a microglial state defined by the expression of the lipid droplet (LD) associated enzyme ACSL1 with ACSL1-positive microglia most abundant in AD patients with the APOE4/4 genotype. In human iPSC-derived microglia (iMG) fibrillar A{beta} (fA{beta}) induces ACSL1 expression, triglyceride synthesis, and LD accumulation in an APOE-dependent manner. Additionally, conditioned media from LD-containing microglia leads to Tau phosphorylation and neurotoxicity in an APOE-dependent manner. Our findings suggest a link between genetic risk factors for AD with microglial LD accumulation and neurotoxic microglial-derived factors, potentially providing novel therapeutic strategies for AD.

neuroscience↗

bioRxiv2020

Aged Breast Extracellular Matrix Drives Mammary Epithelial Cells to an Invasive and Cancer-Like Phenotype

Age is a major risk factor for cancer. While the importance of age related genetic alterations in cells on cancer progression is well documented, the effect of aging extracellular matrix (ECM) has been overlooked. Here, we show for the first time that the aging breast ECM is sufficient to drive normal mammary epithelial cells (KTB21) to a more invasive and cancer-like phenotype, while promoting motility and invasiveness in MDA-MB-231 cells. E-cadherin membrane localization was lost in KTB21 cells cultured on the decellularized breast matrix from aged mice. Cell motility, cell invasion, and inflammatory cytokine and cancer-related protein production were increased significantly on the aged matrix, and many genes related to invasion were upregulated. Strikingly, we showed using single cell RNA sequencing that the aged matrix led to enrichment of a subpopulation of KTB21 cells that highly expressed epithelial-mesenchymal transition (EMT) and invasion-related genes. Lysyl oxidase (LOX) knockdown reverted the aged matrix-induced changes to the young levels; LOX siRNA treatment prevented the loss of E-cadherin membrane localization, and reduced cell motility, cell invasion, and cytokine and cancer-related protein production. Finally, we showed that the biophysical, mechanical and biochemical properties of the breast ECM were altered dramatically upon aging. Analyzing these factors and studying the differential response of the epithelial cells to young and aged ECMs could lead to identification of new targets for cancer treatment and could pave the way for the discovery of new therapeutic options.

cancer biology↗