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Open Access Publications from the University of California

Scholarly Works (4 results)

  • Thesis
  • Peer Reviewed
UC San Diego Electronic Theses and Dissertations (2023)

Tumor-associated macrophages (TAMs) create an immunosuppressive tumor microenvironment (TME) that will promote tumor progression. The goal of this project is to understand whether the pattern of TAMs in a tumor is determined by the tumor cells or by the host tissue environment. Knowing how the phenotype of TAMs is determined will help us better target TAMs to improve cancer patient’s outcome. Moreover, another goal of this project is to understand whether the TAMs that develop in a primary tumor have the same phenotype as those that develop in subsequent metastases. Comparing gene expression profiles between TAMs in different tissues can provide future directions to improve cancer therapies so that we can better target TAMs in order to effectively eradicate primary and metastatic tumors.

Using flow cytometry to examine like tumors growing in different tissues, we found that subcutaneous, orthotopic, and intravenous LLC tumor models all have similar TAM profiles that are distinct from genetically engineered CC10Cre KrasG12D p53-/- spontaneous lung tumor models. In addition, using single-cell sequencing to investigate the PyMT primary mammary gland tumors and metastatic lung tumor the and CC10Cre KrasG12D p53-/- spontaneous lung tumors, we can conclude that the TAM profile of the primary tumor and subsequent metastasized tumor have similar TAM profiles. As a result, we can conclude that the TAM profile is dependent on the tumor cells themselves instead of the microenvironment.

    • Article
    • Peer Reviewed
    UC San Diego Previously Published Works (2022)
    Myeloid cells play key roles in cancer immune suppression and tumor progression. In response to tumor derived factors, circulating monocytes and granulocytes extravasate into the tumor parenchyma where they stimulate angiogenesis, immune suppression and tumor progression. Chemokines, cytokines and interleukins stimulate PI3Kγ-mediated Rap1 activation, leading to conformational changes in integrin α4β1 that promote myeloid cell extravasation and tumor inflammation Here we show that PI3Kγ activates a high molecular weight form of myosin light chain kinase, MLCK210, that promotes myosin-dependent Rap1 GTP loading, leading to integrin α4β1 activation. Genetic or pharmacological inhibition of MLCK210 suppresses integrin α4β1 activation, as well as tumor inflammation and progression. These results demonstrate a critical role for myeloid cell MLCK210 in tumor inflammation and serve as basis for the development of alternative approaches to develop immune oncology therapeutics.
      Cover page: PI3Kγ stimulates a high molecular weight form of myosin light chain kinase to promote myeloid cell adhesion and tumor inflammation
      • Article
      • Peer Reviewed
      UC San Diego Previously Published Works (2023)
      Biallelic mutations in the gene that encodes the enzyme N-glycanase 1 (NGLY1) cause a rare disease with multi-symptomatic features including developmental delay, intellectual disability, neuropathy, and seizures. NGLY1s activity in human neural cells is currently not well understood. To understand how NGLY1 gene loss leads to the specific phenotypes of NGLY1 deficiency, we employed direct conversion of NGLY1 patient-derived induced pluripotent stem cells (iPSCs) to functional cortical neurons. Transcriptomic, proteomic, and functional studies of iPSC-derived neurons lacking NGLY1 function revealed several major cellular processes that were altered, including protein aggregate-clearing functionality, mitochondrial homeostasis, and synaptic dysfunctions. These phenotypes were rescued by introduction of a functional NGLY1 gene and were observed in iPSC-derived mature neurons but not astrocytes. Finally, laser capture microscopy followed by mass spectrometry provided detailed characterization of the composition of protein aggregates specific to NGLY1-deficient neurons. Future studies will harness this knowledge for therapeutic development.
        Cover page: NGLY1 mutations cause protein aggregation in human neurons.
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2024)
        Virulent infectious agents such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and methicillin-resistant Staphylococcus aureus (MRSA) induce tissue damage that recruits neutrophils, monocyte, and macrophages, leading to T cell exhaustion, fibrosis, vascular leak, epithelial cell depletion, and fatal organ damage. Neutrophils, monocytes, and macrophages recruited to pathogen-infected lungs, including SARS-CoV-2-infected lungs, express phosphatidylinositol 3-kinase gamma (PI3Kγ), a signaling protein that coordinates both granulocyte and monocyte trafficking to diseased tissues and immune-suppressive, profibrotic transcription in myeloid cells. PI3Kγ deletion and inhibition with the clinical PI3Kγ inhibitor eganelisib promoted survival in models of infectious diseases, including SARS-CoV-2 and MRSA, by suppressing inflammation, vascular leak, organ damage, and cytokine storm. These results demonstrate essential roles for PI3Kγ in inflammatory lung disease and support the potential use of PI3Kγ inhibitors to suppress inflammation in severe infectious diseases.
          Cover page: PI3Kγ inhibition circumvents inflammation and vascular leak in SARS-CoV-2 and other infections
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