Ian Guldner

All Publications

• APOE4/4 is linked to damaging lipid droplets in Alzheimer's diseasemicroglia. Nature Haney, M. S., Palovics, R., Munson, C. N., Long, C., Johansson, P. K., Yip, O., Dong, W., Rawat, E., West, E., Schlachetzki, J. C., Tsai, A., Guldner, I. H., Lamichhane, B. S., Smith, A., Schaum, N., Calcuttawala, K., Shin, A., Wang, Y., Wang, C., Koutsodendris, N., Serrano, G. E., Beach, T. G., Reiman, E. M., Glass, C. K., Abu-Remaileh, M., Enejder, A., Huang, Y., Wyss-Coray, T. 2024

  Abstract

  Several genetic risk factors for Alzheimer's disease implicate genes involved in lipid metabolism and many of these lipid genes are highly expressed in glial cells1. However, the relationship between lipid metabolism in glia and Alzheimer's disease pathology remains poorly understood. Through single-nucleus RNA sequencing of brain tissue in Alzheimer's disease, we have identified a microglial state defined by the expression of the lipid droplet-associated enzyme ACSL1 with ACSL1-positive microglia being most abundant in patients with Alzheimer's disease having the APOE4/4 genotype. In human induced pluripotent stem cell-derived microglia, fibrillar Abeta induces ACSL1 expression, triglyceride synthesis and lipid droplet accumulation in an APOE-dependent manner. Additionally, conditioned media from lipid droplet-containing microglia lead to Tau phosphorylation and neurotoxicity in an APOE-dependent manner. Our findings suggest a link between genetic risk factors for Alzheimer's disease with microglial lipid droplet accumulation and neurotoxic microglia-derived factors, potentially providing therapeutic strategies for Alzheimer's disease.

  View details for DOI 10.1038/s41586-024-07185-7

  View details for PubMedID 38480892

• Atlas of the aging mouse brain reveals white matter as vulnerable foci. Cell Hahn, O., Foltz, A. G., Atkins, M., Kedir, B., Moran-Losada, P., Guldner, I. H., Munson, C., Kern, F., Pálovics, R., Lu, N., Zhang, H., Kaur, A., Hull, J., Huguenard, J. R., Grönke, S., Lehallier, B., Partridge, L., Keller, A., Wyss-Coray, T. 2023

  Abstract

  Aging is the key risk factor for cognitive decline, yet the molecular changes underlying brain aging remain poorly understood. Here, we conducted spatiotemporal RNA sequencing of the mouse brain, profiling 1,076 samples from 15 regions across 7 ages and 2 rejuvenation interventions. Our analysis identified a brain-wide gene signature of aging in glial cells, which exhibited spatially defined changes in magnitude. By integrating spatial and single-nucleus transcriptomics, we found that glial aging was particularly accelerated in white matter compared with cortical regions, whereas specialized neuronal populations showed region-specific expression changes. Rejuvenation interventions, including young plasma injection and dietary restriction, exhibited distinct effects on gene expression in specific brain regions. Furthermore, we discovered differential gene expression patterns associated with three human neurodegenerative diseases, highlighting the importance of regional aging as a potential modulator of disease. Our findings identify molecular foci of brain aging, providing a foundation to target age-related cognitive decline.

  View details for DOI 10.1016/j.cell.2023.07.027

  View details for PubMedID 37591239

• A nanotherapeutic approach to selectively eliminate metastatic breast cancer cells by targeting cell surface GRP78. Nanoscale Shin, J., Kim, B., Lager, T. W., Mejia, F., Guldner, I., Conner, C., Zhang, S., Panopoulos, A. D., Bilgicer, B. 2023

  Abstract

  Here, rational engineering of doxorubicin prodrug loaded peptide-targeted liposomal nanoparticles to selectively target metastatic breast cancer cells in vivo is described. Glucose-regulated protein 78 (GRP78), a heat shock protein typically localized in the endoplasmic reticulum in healthy cells, has been identified to home to the cell surface in certain cancers, and thus has emerged as a promising therapeutic target. Recent reports indicated GRP78 to be expressed on the cell surface of an aggressive subpopulation of stem-like breast cancer cells that exhibit metastatic potential. In this study, a targeted nanoparticle formulation with a GRP78-binding peptide (Kd of 7.4 ± 1.0 μM) was optimized to selectively target this subpopulation. In vitro studies with breast cancer cell lines showed the targeted nanoparticle formulation (TNPGRP78pep) achieved enhanced cellular uptake, while maintaining selectivity over the control groups. In vivo, TNPGRP78pep loaded with doxorubicin prodrug was evaluated using a lung metastatic mouse model and demonstrated inhibition of breast cancer cell seeding to lungs down at the level of negative control groups. Combined, this study established that specific-targeting of surface GRP78 expressing a subpopulation of aggressive breast cancer cells was able to inhibit breast cancer metastasis to lungs, and underpinned the significance of GRP78 in breast cancer metastasis.

  View details for DOI 10.1039/d3nr00800b

  View details for PubMedID 37526009

• APOE4/4 is linked to damaging lipid droplets in Alzheimer's microglia. bioRxiv : the preprint server for biology Haney, M. S., Pálovics, R., Munson, C. N., Long, C., Johansson, P., Yip, O., Dong, W., Rawat, E., West, E., Schlachetzki, J. C., Tsai, A., Guldner, I. H., Lamichhane, B. S., Smith, A., Schaum, N., Calcuttawala, K., Shin, A., Wang, Y. H., Wang, C., Koutsodendris, N., Serrano, G. E., Beach, T. G., Reiman, E. M., Glass, C. K., Abu-Remaileh, M., Enejder, A., Huang, Y., Wyss-Coray, T. 2023

  Abstract

  Several genetic risk factors for Alzheimer's 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 Aβ (fAβ) 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.

  View details for DOI 10.1101/2023.07.21.549930

  View details for PubMedID 37546938

  View details for PubMedCentralID PMC10401952

• Activated immune cells drive neurodegeneration NATURE Guldner, I. H., Wyss-Coray, T. 2023; 615 (7953): 588-589

  View details for Web of Science ID 000961443400002

• Activated immune cells drive neurodegeneration in an Alzheimer's model. Nature Guldner, I. H., Wyss-Coray, T. 2023; 615 (7953): 588-589

  View details for DOI 10.1038/d41586-023-00600-5

  View details for PubMedID 36890310

• Isolation of mouse brain-infiltrating leukocytes for single cell profiling of epitopes and transcriptomes. STAR protocols Guldner, I. H., Golomb, S. M., Wang, Q., Wang, E., Zhang, S. 2021; 2 (2): 100537

  Abstract

  High dimensional compositional and transcriptional profiling of heterogeneous brain-infiltrating leukocytes can lead to novel biological and therapeutic discoveries. High-quality single-cell leukocyte preparations are a prerequisite for optimal single cell profiling. Here, we describe a protocol for epitope and RNA-preserving dissociation of adult mouse brains and subsequent leukocyte purification and staining, which is adaptable to homeostatic and pathogenic brains. Leukocyte preparation following this protocol permits exquisite single-cell surface protein and RNA profiling in applications including CyTOF and CITE-seq. For complete details on the use and execution of this protocol, please refer to Guldner etal. (2020) and Golomb etal. (2020).

  View details for DOI 10.1016/j.xpro.2021.100537

  View details for PubMedID 34036283

• Single-cell profiling guided combinatorial immunotherapy for fast-evolving CDK4/6 inhibitor-resistant HER2-positive breast cancer NATURE COMMUNICATIONS Wang, Q., Guldner, I. H., Golomb, S. M., Sun, L., Harris, J. A., Lu, X., Zhang, S. 2019; 10: 3817

  Abstract

  Acquired resistance to targeted cancer therapy is a significant clinical challenge. In parallel with clinical trials combining CDK4/6 inhibitors to treat HER2+ breast cancer, we sought to prospectively model tumor evolution in response to this regimen in vivo and identify a clinically actionable strategy to combat drug resistance. Despite a promising initial response, acquired resistance emerges rapidly to the combination of anti-HER2/neu antibody and CDK4/6 inhibitor Palbociclib. Using high-throughput single-cell profiling over the course of treatments, we reveal a distinct immunosuppressive immature myeloid cell (IMC) population to infiltrate the resistant tumors. Guided by single-cell transcriptome analysis, we demonstrate that combination of IMC-targeting tyrosine kinase inhibitor cabozantinib and immune checkpoint blockade enhances anti-tumor immunity, and overcomes the resistance. Furthermore, sequential combinatorial immunotherapy enables a sustained control of the fast-evolving CDK4/6 inhibitor-resistant tumors. Our study demonstrates a translational framework for treating rapidly evolving tumors through preclinical modeling and single-cell analyses.

  View details for DOI 10.1038/s41467-019-11729-1

  View details for Web of Science ID 000482398900019

  View details for PubMedID 31444334

  View details for PubMedCentralID PMC6707314

• Death effector domain-containing protein induces vulnerability to cell cycle inhibition in triple-negative breast cancer NATURE COMMUNICATIONS Ni, Y., Schmidt, K. R., Werner, B. A., Koenig, J. K., Guldner, I. H., Schnepp, P. M., Tan, X., Jiang, L., Host, M., Sun, L., Howe, E. N., Wu, J., Littlepage, L. E., Nakshatri, H., Zhang, S. 2019; 10: 2860

  Abstract

  Lacking targetable molecular drivers, triple-negative breast cancer (TNBC) is the most clinically challenging subtype of breast cancer. In this study, we reveal that Death Effector Domain-containing DNA-binding protein (DEDD), which is overexpressed in > 60% of TNBCs, drives a mitogen-independent G1/S cell cycle transition through cytoplasm localization. The gain of cytosolic DEDD enhances cyclin D1 expression by interacting with heat shock 71 kDa protein 8 (HSC70). Concurrently, DEDD interacts with Rb family proteins and promotes their proteasome-mediated degradation. DEDD overexpression renders TNBCs vulnerable to cell cycle inhibition. Patients with TNBC have been excluded from CDK 4/6 inhibitor clinical trials due to the perceived high frequency of Rb-loss in TNBCs. Interestingly, our study demonstrated that, irrespective of Rb status, TNBCs with DEDD overexpression exhibit a DEDD-dependent vulnerability to combinatorial treatment with CDK4/6 inhibitor and EGFR inhibitor in vitro and in vivo. Thus, our study provided a rationale for the clinical application of CDK4/6 inhibitor combinatorial regimens for patients with TNBC.

  View details for DOI 10.1038/s41467-019-10743-7

  View details for Web of Science ID 000473132200024

  View details for PubMedID 31253784

  View details for PubMedCentralID PMC6599020