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Open Access Publications from the University of California

Scholarly Works (46 results)

  • Thesis
  • Peer Reviewed
UCLA Electronic Theses and Dissertations (2016)

Spinal cord injuries can lead to life long debilitations, in some cases, paralysis. Patients suffering with spinal cord injury, however, may find hope for improved functionality of debilitated limbs via cell transplantation. Because adipose tissue is an abundant cell source that can be harbored from a patient through liposuction, we investigated and compared the differential propensity of brown and white adipose tissue-derived stem cells to generate neuronal cells. Although previous studies have shown white adipose stomal cells (ASCs) and dedifferentiated fat (DFAT) cells contain neurogenic potential, there has not been studies focused on ASCs and DFAT cells derived from brown adipose tissue, a subtype functionally different from white adipose tissue. In this study, we therefore focus on determining the differential potential of white and brown-derived ASCs and DFAT cells to generate neural cells.

To study the difference we cultured these cells in neural induction medium or “basic medium”, i.e 10% FBS in DMEM, and compared their expression of neural precursor genes, neuronal genes and glial genes. Our results indicate brown-derived adipose tissue as compared to white-derived adipose tissue contains a greater potential to become neuronal or glial-like cells; brown-derived ASCs cultured with 20% serum replacement in DMEM, showed significant increases in its neuroprogenitor while brown-derived DFAT cells in basic medium contained a higher potential to generate glial-like, s100B+ cells. Therefore, our results suggest brown adipose tissue-derived stem cells would be a more ideal source of neural stem cells than the previous white adipose tissue-derived stem cells.

    Cover page: Brown vs. White Adipose Tissue: Brown Adipose Tissue is a Source of Multipoint Stem Cells with Greater Propensity for Neurogenesis
    • Article
    • Peer Reviewed
    UCLA Previously Published Works (2023)
    Differentiation trajectory from ECs to EC-like myofibroblasts and myofibroblasts may pass through a mesenchymal stage. This trajectory exists in a quiescent state in healthy lungs and may be activated when pathological stimuli trigger pulmonary fibrosis. https://bit.ly/3QWfgyS
      Cover page: Reply: Transitioning endothelial cells contribute to pulmonary fibrosis.
      • Article
      • Peer Reviewed
      UCLA Previously Published Works (2015)
        • Thesis
        • Peer Reviewed
        UCLA Electronic Theses and Dissertations (2012)

        Multipotent CVCs are used as models for atherosclerotic lesion cells due to their capacity to calcify, but the molecular or cellular mechanisms involved are not completely known. Recent work has reported that stem cell-associated factors show patterned responses in vertebrate segmentation and other cells in embryonic development, suggesting that oscillatory expression is a general feature for many cellular events. In this study, we explored connections between the expression of multipotency markers and pattern formations in CVCs. Control CVCs, BMP-4 treated CVCs, and MGP depleted CVCs were cultured separately in a two-week time period, and the expression of Sox2, Nanog, Klf4, and Oct-3/4 were analyzed with real-time PCR. Furthermore, the relationship between the osteogenic potential of CVC and these genes was briefly explored. Our results suggest that CVCs may exhibit oscillatory genetic expression as they form patterns, and that BMP inhibition by MGP is essential to maintaining oscillations and pattern formations.

          Cover page: Oscillatory Expression of Stem Cell-associated Genes in Pattern Forming Calcifying Vascular Cells
          • Article
          • Peer Reviewed
          UCLA Previously Published Works (2022)
          Multipotent cells derived from white adipose tissue have been shown to differentiate into multiple lineages including neurogenic lineages. However, the high innervation of brown adipose tissue by the sympathetic nervous system suggest it might be a better source of neural precursor cells. To investigate potential differences between white and brown progenitors, we cultured white and brown dedifferentiated fat (wDFAT and brDFAT) cells from mouse and human adipose tissue and compared marker expression of neural precursors, and neuronal and glial cells, using fluorescence-activated cell sorting, bright-field imaging, immunofluorescence, and RNA analysis by qPCR. The results showed that both wDFAT and brDFAT cells had the capacity to generate neuronal and glial-like cells under neurogenic conditions. However, the brDFAT cells exhibited enhanced propensity for neurogenic differentiation. The neurogenic cells were at least in part derived from Adiponectin-expressing cells. TdTomato-expressing cells derived from Adiponectin (Adipoq) Cre ERT2 -tdTomato flox/flox mice gave rise to individual cells and cell clusters with neurogenic characteristics. Moreover, human brDFAT cells demonstrated a similar ability to undergo neurogenic differentiation after treatment with neurogenic medium, as assessed by immunofluorescence and qPCR. Together, our results support that brDFAT cells have ability to undergo neurogenic differentiation.
            Cover page: Progenitor cells from brown adipose tissue undergo neurogenic differentiation.
            • Thesis
            • Peer Reviewed
            UCLA Electronic Theses and Dissertations (2013)

            The formation of the heart, cardiomyogenesis, is highly regulated to ensure proper formation and function. The objective of this study was to examine the role of bone morphogenetic protein (BMP) signaling in cardiomyogenesis. In order to accomplish this, we used an adipocyte-derived multipotent cell model termed dedifferentiated (DFAT) fat cells which readily differentiate into cardiomyocytes. Specifically, we investigated the effects of treating DFAT cells with BMP10 and crossveinless-2 (CV2), a BMP inhibitor. BMP10 is expressed exclusively in the heart and activates the activin receptor-like kinase 1 (ALK1) which is a BMP receptor that induces expression of cardiogenic factors such as Nkx2.5 through the SMAD signaling pathway. CV2 was investigated because it has been shown to modulate BMP signaling. We chose to examine BMP10's role in cardiomyogenesis because it is structurally similar to BMP9, which regulates vascular cell differentiation, and is expressed early in the developing heart. We hypothesized that BMP10 induced proliferation of cardiac progenitor cells and CV2 induced their differentiation.

            We demonstrated that CV2 binds directly to BMP10 and inhibits BMP10 from initiating SMAD signaling using co-immunoprecipitation and a luciferase reporter gene assay. We showed that BMP10 treatment induced proliferation of DFAT cells using a 3H-thymidine proliferation assay, whereas CV2 proliferation levels were similar to those produced by control treatments. However, CV2 induced differentiation of DFAT cells into cardiomyocytes, as demonstrated by the induction of expression of cardiomyocyte markers by real-time PCR. Expression levels of Nkx2.5 and troponin I, which are early and late cardiomyocyte markers, respectively, were studied. Treatment with BMP10 showed an increase in Nkx2.5 expression at Day 7 after treatment, whereas CV2 treatment showed an increase in troponin I expression at Day 14. These results were corroborated by immunohistochemistry studies using antibodies against troponin I, which indicates the presence of cardiomyocytes, and α-myosin heavy chain (α-MHC) which indicates the presence of muscle tissue. The results indicated that BMP10 increased the number of early cardiomyocyte progenitor cells, whereas CV2 induced differentiation of DFAT cells into cardiomyocyte-like cells that were electrically active and beating. Taken together, these results supported a model where cardiomyogenesis occurs via a two-step mechanism. First, BMP10 increases the pool of cardiac progenitor cells. Then, once the progenitor pool has been expanded sufficiently, CV2 inhibits BMP10 and triggers cardiomyocyte differentiation.

            Our findings may improve our understanding of the mechanism involved in cardiomyogenesis and enhance our ability to generate cardiomyocytes from DFAT cells or other stem cells.

              Cover page: The Role of Bone Morphogenetic Protein 10 (BMP10) and Crossveinless 2 (CV2) in Cardiomyogenesis
              • Article
              • Peer Reviewed
              UCLA Previously Published Works (2021)
              Vascular calcification (VC) increases morbidity and mortality and constitutes a significant obstacle during percutaneous interventions and surgeries. On a cellular and molecular level, VC is a highly regulated process that involves abnormal cell transitions and osteogenic differentiation, re-purposing of signaling pathways normally used in bone, and even formation of osteoclast-like cells. Endothelial cells have been shown to contribute to VC through a variety of means. This includes direct contributions of osteoprogenitor cells generated through endothelial-mesenchymal transitions in activated endothelium, with subsequent migration into the vessel wall. The endothelium also secretes pro-osteogenic growth factors, such as bone morphogenetic proteins, inflammatory mediators and cytokines in conditions like hyperlipidemia, diabetes, and renal failure. High phosphate levels caused by renal disease have deleterious effects on the endothelium, and induction of tissue non-specific alkaline phosphatase adds to the calcific process. Furthermore, endothelial activation promotes proteolytic destruction of the internal elastic lamina that serves, among other things, as a stabilizer of the endothelium. Appropriate bone mineralization is highly dependent on active angiogenesis, but it is unclear whether the same relationship exists in VC. Through its location facing the vascular lumen, the endothelium is the first to encounter circulating factor and bone marrow-derived cells that might contribute to osteoclast-like versus osteoblast-like cells in the vascular wall. In the same way, the endothelium may be the easiest target to reach with treatments aimed at limiting calcification. This review provides a brief summary of the contributions of the endothelium to VC as we currently know them.
                Cover page: Contributions of the Endothelium to Vascular Calcification.
                • Article
                • Peer Reviewed
                UCLA Previously Published Works (2021)
                Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a highly conserved enzyme involved in the ubiquitous process of glycolysis and presents a loop (residues 208-215 of Escherichia coli GAPDH) in two alternative conformations (I and II). It is uncertain what triggers this loop rearrangement, as well as which is the precise site from which phosphate attacks the thioacyl intermediate precursor of 1,3-bisphosphoglycerate (BPG). To clarify these uncertainties, we determined the crystal structures of complexes of wild-type GAPDH (WT) with NAD and phosphate or G3P, and of essentially inactive GAPDH mutants (C150S, H177A), trapping crystal structures for the thioacyl intermediate or for ternary complexes with NAD and either phosphate, BPG, or G3P. Analysis of these structures reported here lead us to propose that phosphate is located in the new Pi site attacks the thioester bond of the thioacyl intermediate to generate 1,3-bisphosphoglyceric acid (BPG). In the structure of the thioacyl intermediate, the mobile loop is in conformation II in subunits O, P, and R, while both conformations coexist in subunit Q. Moreover, only the Q subunit hosts bound NADH. In the R subunit, only the pyrophosphate part of NADH is well defined, and NADH is totally absent from the O and P subunits. Thus, the change in loop conformation appears to occur after NADH is produced, before NADH is released. In addition, two new D-glyceraldehyde-3-phosphate (G3P) binding forms are observed in WT.NAD.G3P and C150A+H177A.NAD.G3P. In summary, this paper improves our understanding of the GAPDH catalytic mechanism, particularly regarding BPG formation.
                  Cover page: Novel Structures of Type 1 Glyceraldehyde-3-phosphate Dehydrogenase from Escherichia coli Provide New Insights into the Mechanism of Generation of 1,3-Bisphosphoglyceric Acid.
                  • Article
                  • Peer Reviewed
                  UCLA Previously Published Works (2019)
                  Growing evidence suggests close associations between periodontitis and atherosclerosis. To further understand the pathological relationships of these associations, we developed periodontitis with ligature placement around maxillary molars or ligature placement in conjunction with Porphyromonas gingivalis lipopolysaccharide injection at the ligature sites (ligature/P.g. LPS) in Apolipoprotein E knock out mice and studied the atherogenesis process in these animals. The mice were fed with high fat diet for 11 weeks and sacrificed for analyzing periodontitis, systemic inflammation, and atherosclerosis. Controls did not develop periodontitis or systemic inflammation and had minimal lipid deposition in the aortas, but mice receiving ligature or ligature/P.g. LPS showed severe periodontitis, systemic inflammation, and aortic plaque formation. The aortic plaque contained abundant macrophages and cells expressing both endothelial and mesenchymal cell markers. The severity of periodontitis was slightly higher in mice receiving ligature/P.g. LPS than ligature alone, and the magnitude of systemic inflammation and aortic plaque formation were also notably greater in the mice with ligature/P.g. LPS. These observations indicate that the development of atherosclerosis is due to systemic inflammation caused by severe periodontitis. In vitro, P.g. LPS enhanced the secretion of pro-inflammatory cytokines from macrophages and increased the adhesion of monocytes to endothelial cells by upregulating the expression of adhesion molecules from endothelial cells. Moreover, secretory proteins, such as TNF-α, from macrophages induced endothelial-mesenchymal transitions of the endothelial cells. Taken together, systemic inflammation induced by severe periodontitis might exacerbate atherosclerosis via, in part, causing aberrant functions of vascular endothelial cells and the activation of macrophages in mice.
                    Cover page: Periodontitis-induced systemic inflammation exacerbates atherosclerosis partly via endothelial–mesenchymal transition in mice
                    • Article
                    • Peer Reviewed
                    UCLA Previously Published Works (2007)
                    Hyperlipoproteinemia represents a constellation of clinical syndromes that frequently includes hypertriglyceridemia. Because of the degree of elevation in the triglyceride levels frequently seen in these syndromes, they are associated with complications not generally observed among those patients with essential hypertriglyceridemia, including as in this case report, recurrent pancreatitis. Here, we present a case of a patient with hyperlipoproteinemia who developed acute worsening of his hypertriglyceridemia and onset of acute panceatitis that became recurrent following elective splenectomy for suspected lymphoma. In particular, we discuss the dietary management of hypertriglyceridemia which significantly reduced the number of episodes of acute pancreatitis in this patient.
                      Cover page: Hypertriglyceridemia and Recurrent Pancreatitis following Splenectomy
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