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Open Access Publications from the University of California

Scholarly Works (12 results)

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

Background: Fibromodulin (FMOD) has been demonstrated to decrease scarring in mouse models. We developed an FMOD-based peptide, F06-C40, which has similar effect as FMOD while being more efficient and less costly to produce. In this study, the effect of FMOD and F06-C40 on scars was tested in porcine models for future preclinical studies.

Methods: Full-thickness incisional wounds were generated on the dorsum of Yorkshire pigs or red Duroc pigs to simulate human normal or hypertrophic scarring. FMOD, F06-C40, or PBS was injected intradermally around the wound edge. At 8 weeks post-injury, scar formation was evaluated by gross appearance, histological analysis, and tensile strength.

Results: FMOD and F06-C40 peptide significantly reduced scar formation and increased tensile strength in both Yorkshire pig and red Duroc pig models.

Conclusion: The results indicate F06-C40 has the potential to be developed as a novel therapeutic for improving wound healing in normal and hypertrophic scarring patients.

    Cover page: Fibromodulin and Its Derivative Reduce Scars in Adult Porcine Models
    • Thesis
    • Peer Reviewed
    UCLA Electronic Theses and Dissertations (2022)

    Scarring and wounds are a significant clinical issue which affects up to 100 million people worldwide. More specifically, as one of the most common and devastating sequelae of uncontrolled diabetes, chronic non-healing diabetic wounds affect an estimated 25% of diabetic patients. Wound healing process is significantly impaired in diabetic patients, including imbalanced production of extracellular matrix components, aberrant cellular infiltration, abnormal fibroblast function, and insufficient angiogenesis. A molecular therapeutic for diabetic wound healing that acts to restore the molecular and cellular processes is needed for successful wound healing. Fibromodulin (FMOD), as a key molecule required for fetal scarless skin repair, can significantly accelerate wound closure, promote angiogenesis, decrease scarring, and improve extracellular matrix organization. Studies have shown FMOD promotes dermal fibroblast migration, myofibroblast differentiation and contraction, which plays an important role in diabetic wound healing process. F06-C40, a FMOD derived peptide acts similar as FMOD protein and is much faster and easier to generate, which can potentially benefit millions of patients. However, the effect of FMOD and its peptide on diabetic wounds remains unknown. In this study, type II diabetic NONcNZO10 mouse model was used to study the effect of FMOD and its peptide in vivo. After full thickness excisional wounds, scar area, capillary formation, and extracellular matrix formation and collagen architecture were determined. In vitro, hyperglycemia-induced fibroblasts and primary human dermal diabetic fibroblasts were treated with FMOD and its derived peptide to study the effect of FMOD and its peptide on diabetic dermal fibroblast proliferation, migration, contraction and invasion. To further investigate the mechanism of FMOD on wound healing in a molecular level, the effect of FMOD on cell adhesion was analyzed and the downstream molecule was studied. In addition, TGF-beta 1 plays an important role in scarring and fibrosis formation. The effect of FMOD on TGF-beta 1 pathway was determined to further elucidate the role of FMOD on wound healing and scar reduction. As a result, FMOD and its peptide successfully accelerated wound closure, reduced scar formation and promoted angiogenesis in vivo. In addition, they promoted diabetic fibroblast migration, contraction and invasion. FMOD promoted fibroblast cell adhesion via integrin. And FMOD shows a down regulation on TGF-beta 1 non-canonical pathway, which is the opposite effect on TGF-beta 1 canonical pathway according to previous studies. Therefore, FMOD and its peptide have the potential to treat diabetic wounds by improving fibroblast characteristics.

      Cover page: Fibromodulin and Its Peptide-based Therapy for Cutaneous and Diabetic Wound Healing
      • Article
      • Peer Reviewed
      UC San Francisco Previously Published Works (2013)
      Allostery in a protein involves effector binding at an allosteric site that changes the structure and/or dynamics at a distant, functional site. In addition to the chemical equilibrium of ligand binding, allostery involves a conformational equilibrium between one protein substate that binds the effector and a second substate that less strongly binds the effector. We run molecular dynamics simulations using simple, smooth energy landscapes to sample specific ligand-induced conformational transitions, as defined by the effector-bound and effector-unbound protein structures. These simulations can be performed using our web server (http://salilab.org/allosmod/). We then develop a set of features to analyze the simulations and capture the relevant thermodynamic properties of the allosteric conformational equilibrium. These features are based on molecular mechanics energy functions, stereochemical effects, and structural/dynamic coupling between sites. Using a machine-learning algorithm on a data set of 10 proteins and 179 mutations, we predict both the magnitude and the sign of the allosteric conformational equilibrium shift by the mutation; the impact of a large identifiable fraction of the mutations can be predicted with an average unsigned error of 1k(B)T. With similar accuracy, we predict the mutation effects for an 11th protein that was omitted from the initial training and testing of the machine-learning algorithm. We also assess which calculated thermodynamic properties contribute most to the accuracy of the prediction.
        Cover page: Impact of Mutations on the Allosteric Conformational Equilibrium
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2016)
        The influenza virus is responsible for millions of cases of severe illness annually. Yearly variance in the effectiveness of vaccination, coupled with emerging drug resistance, necessitates the development of new drugs to treat influenza infections. One attractive target is the RNA-dependent RNA polymerase PA subunit. Herein we report the development of inhibitors of influenza PA endonuclease derived from lead compounds identified from a metal-binding pharmacophore (MBP) library screen. Pyromeconic acid and derivatives thereof were found to be potent inhibitors of endonuclease. Guided by modeling and previously reported structural data, several sublibraries of molecules were elaborated from the MBP hits. Structure-activity relationships were established, and more potent molecules were designed and synthesized using fragment growth and fragment merging strategies. This approach ultimately resulted in the development of a lead compound with an IC50 value of 14 nM, which displayed an EC50 value of 2.1 μM against H1N1 influenza virus in MDCK cells.
          Cover page: Fragment-Based Identification of Influenza Endonuclease Inhibitors
          • Article
          • Peer Reviewed
          UC Davis Previously Published Works (2021)
          Reinforcement learning models postulate that neurons that release dopamine encode information about action and action outcome, and provide a teaching signal to striatal spiny projection neurons in the form of dopamine release1. Dopamine is thought to guide learning via dynamic and differential modulation of protein kinase A (PKA) in each class of spiny projection neuron2. However, the real-time relationship between dopamine and PKA in spiny projection neurons remains untested in behaving animals. Here we monitor the activity of dopamine-releasing neurons, extracellular levels of dopamine and net PKA activity in spiny projection neurons in the nucleus accumbens of mice during learning. We find positive and negative modulation of dopamine that evolves across training and is both necessary and sufficient to explain concurrent fluctuations in the PKA activity of spiny projection neurons. Modulations of PKA in spiny projection neurons that express type-1 and type-2 dopamine receptors are dichotomous, such that these neurons are selectively sensitive to increases and decreases, respectively, in dopamine that occur at different phases of learning. Thus, PKA-dependent pathways in each class of spiny projection neuron are asynchronously engaged by positive or negative dopamine signals during learning.
            Cover page: Cell-type-specific asynchronous modulation of PKA by dopamine in learning
            • Article
            • Peer Reviewed
            UC San Diego Previously Published Works (2007)

            Calnuc is a calcium (Ca2+) binding protein found in both Golgi and cytoplasm, and it may play a role in G protein- and Ca2+-regulated signal transduction events. This study was designed to investigate the possibility of whether Calnuc protein might be a tumor-associated antigen (TAA) that induces autoantibody response in human cancers, and to evaluate the feasibility of the Calnuc antigen-antibody system as a marker in cancer detection. Purified full-length recombinant Calnuc protein was used as an antigen in enzyme-linked immunoassay and Western blotting for the detection of autoantibodies in cancers. Sera from 447 patients with 9 different types of cancer were analyzed. Although the frequency of autoantibody to Calnuc was found to be 4.7% in total groups of cancer, it was not significantly different to that of normal individuals (1.2%). However, the frequency of autoantibody to Calnuc in colon cancer (11.5%) was significantly higher than that in normal individuals (1.2%). The expression analysis of Calnuc in multiple colon cancer tissues by immunohistochemistry on tissue array further confirmed the high specificity of Calnuc in colon cancer. Of 69 colon cancer tissue specimens examined, 41 tissues (59.4%) overexpressed Calnuc, while normal colon tissues did not show any expression of Calnuc. The subcellular distribution analysis of Calnuc examined by subcellular fractionation and immunofluorescence indicates that Calnuc is a membrane associated protein and mostly distributed in Golgi, which is consistent with previous reports. With adding Calnuc into a TAA array (including p53, c-myc, cyclin B1, cyclin D1), the cumulative frequency of antibody to multiple TAAs in colon cancer was raised to 65.4% which is significantly higher than the cumulative frequency in normal individuals (6.1%). This indicates that a mini-array of multiple TAAs which includes Calnuc might provide a novel non-invasive approach to enhance antibody detection for colon cancer diagnosis.

              Cover page: Autoantibodies to Ca2+ binding protein Calnuc is a potential marker in colon cancer detection.
              • Article
              • Peer Reviewed
              UC San Diego Previously Published Works (2015)
              Histone deacetylase inhibitors (HDACi) target abnormal epigenetic states associated with a variety of pathologies, including cancer. Here, the development of a prodrug of the canonical broad-spectrum HDACi suberoylanilide hydroxamic acid (SAHA) is described. Although hydroxamic acids are utilized universally in the development of metalloenzyme inhibitors, they are considered to be poor pharmacophores with reduced activity in vivo. We developed a prodrug of SAHA by appending a promoiety, sensitive to thiols, to the hydroxamic acid warhead (termed SAHA-TAP). After incubation of SAHA-TAP with an HDAC, the thiol of a conserved HDAC cysteine residue becomes covalently tagged with the promoiety, initiating a cascade reaction that leads to the release of SAHA. Mass spectrometry and enzyme kinetics experiments validate that the cysteine residue is covalently appended with the TAP promoiety. SAHA-TAP demonstrates cytotoxicity activity against various cancer cell lines. This strategy represents an original prodrug design with a dual mode of action for HDAC inhibition.
                Cover page: Dual-Mode HDAC Prodrug for Covalent Modification and Subsequent Inhibitor Release
                • Article
                • Peer Reviewed
                UC Davis Previously Published Works (2017)
                Glycolysis was reported to have a positive correlation with radioresistance. Our previous study found that the miR-33a functioned as a tumor suppressor in malignant melanoma by targeting hypoxia-inducible factor1-alpha (HIF-1α), a gene known to promote glycolysis. However, the role of miR-33a-5p in radiosensitivity remains to be elucidated. We found that miR-33a-5p was downregulated in melanoma tissues and cells. Cell proliferation was downregulated after overexpression of miR-33a-5p in WM451 cells, accompanied by a decreased level of glycolysis. In contrast, cell proliferation was upregulated after inhibition of miR-33a-5p in WM35 cells, accompanied by increased glycolysis. Overexpression of miR-33a-5p enhanced the sensitivity of melanoma cells to X-radiation by MTT assay, while downregulation of miR-33a-5p had the opposite effects. Finally, in vivo experiments with xenografts in nude mice confirmed that high expression of miR-33a-5p in tumor cells increased radiosensitivity via inhibiting glycolysis. In conclusions, miR-33a-5p promotes radiosensitivity by negatively regulating glycolysis in melanoma.
                  Cover page: microRNA-33a-5p increases radiosensitivity by inhibiting glycolysis in melanoma
                  • Article
                  • Peer Reviewed
                  UCLA Previously Published Works (2016)
                  In contrast to adult and late-gestation fetal skin wounds, which heal with scar, early-gestation fetal skin wounds display a remarkable capacity to heal scarlessly. Although the underlying mechanism of this transition from fetal-type scarless healing to adult-type healing with scar has been actively investigated for decades, in utero restoration of scarless healing in late-gestation fetal wounds has not been reported. In this study, using loss- and gain-of-function rodent fetal wound models, we identified that fibromodulin (Fm) is essential for fetal-type scarless wound healing. In particular, we found that loss of Fm can eliminate the ability of early-gestation fetal rodents to heal without scar. Meanwhile, administration of fibromodulin protein (FM) alone was capable of restoring scarless healing in late-gestation rat fetal wounds, which naturally heal with scar, as characterized by dermal appendage restoration and organized collagen architectures that were virtually indistinguishable from those in age-matched unwounded skin. High Fm levels correlated with decreased transforming growth factor (TGF)-β1 expression and scarless repair, while low Fm levels correlated with increased TGF-β1 expression and scar formation. This study represents the first successful in utero attempt to induce scarless repair in late-gestation fetal wounds by using a single protein, Fm, and highlights the crucial role that the FM-TGF-β1 nexus plays in fetal-type scarless skin repair.
                    Cover page: Fibromodulin Is Essential for Fetal-Type Scarless Cutaneous Wound Healing
                    • Article
                    • Peer Reviewed
                    UC San Diego Previously Published Works (2016)
                    Although autophagy is most critical for survival of cancer cells, especially in fast-growing tumors, the mechanism remains to be fully characterized. Herein we report that PSMD10/gankyrin promotes autophagy in hepatocellular carcinoma (HCC) in response to starvation or stress through 2 complementary routes. PSMD10 was physically associated with ATG7 in the cytoplasm, and this association was enhanced by initial nutrient deprivation. Subsequently, PSMD10 translocated into the nucleus and bound cooperatively with nuclear HSF1 (heat shock transcription factor 1) onto the ATG7 promoter, upregulated ATG7 expression in the advanced stage of starvation. Intriguingly, the type of PSMD10-mediated autophagy was independent of the proteasome system, although PSMD10 has been believed to be an indispensable chaperone for assembly of the 26S proteasome. A significant correlation between PSMD10 expression and ATG7 levels was detected in human HCC biopsies, and the combination of these 2 parameters is a powerful predictor of poor prognosis. The median survival of sorafenib-treated HCC patients with high expression of PSMD10 was much shorter than those with low expression of PSMD10. Furthermore, PSMD10 augmented autophagic flux to resist sorafenib or conventional chemotherapy, and inhibition of autophagy suppressed PSMD10-mediated resistance. We conclude that these results present a novel mechanism involving modulation of ATG7 by PSMD10 in sustaining autophagy, promoting HCC cell survival against starvation or chemotherapy. Targeting of PSMD10 might therefore be an attractive strategy in HCC treatment by suppressing autophagy and inducing HCC cell sensitivity to drugs.
                      Cover page: PSMD10/gankyrin induces autophagy to promote tumor progression through cytoplasmic interaction with ATG7 and nuclear transactivation of ATG7 expression.
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