Publications by authors named "Julia Zhou"

8 Publications

  • Page 1 of 1

Lure-and-kill macrophage nanoparticles alleviate the severity of experimental acute pancreatitis.

Nat Commun 2021 07 6;12(1):4136. Epub 2021 Jul 6.

Department of Nanoengineering, Chemical Engineering Program, Moores Cancer Center, University of California San Diego, La Jolla, CA, USA.

Acute pancreatitis is a disease associated with suffering and high lethality. Although the disease mechanism is unclear, phospholipase A2 (PLA2) produced by pancreatic acinar cells is a known pathogenic trigger. Here, we show macrophage membrane-coated nanoparticles with a built-in 'lure and kill' mechanism (denoted 'MΦ-NP(L&K)') for the treatment of acute pancreatitis. MΦ-NP(L&K) are made with polymeric cores wrapped with natural macrophage membrane doped with melittin and MJ-33. The membrane incorporated melittin and MJ-33 function as a PLA2 attractant and a PLA2 inhibitor, respectively. These molecules, together with membrane lipids, work synergistically to lure and kill PLA2 enzymes. These nanoparticles can neutralize PLA2 activity in the sera of mice and human patients with acute pancreatitis in a dose-dependent manner and suppress PLA2-induced inflammatory response accordingly. In mouse models of both mild and severe acute pancreatitis, MΦ-NP(L&K) confer effective protection against disease-associated inflammation, tissue damage and lethality. Overall, this biomimetic nanotherapeutic strategy offers an anti-PLA2 treatment option that might be applicable to a wide range of PLA2-mediated inflammatory disorders.
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http://dx.doi.org/10.1038/s41467-021-24447-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8260623PMC
July 2021

Neutrophil membrane-coated nanoparticles inhibit synovial inflammation and alleviate joint damage in inflammatory arthritis.

Nat Nanotechnol 2018 12 3;13(12):1182-1190. Epub 2018 Sep 3.

Department of NanoEngineering and Moores Cancer Center, University of California San Diego, La Jolla, CA, USA.

Rheumatoid arthritis is a common chronic inflammatory disorder and a major cause of disability. Despite the progress made with recent clinical use of anti-cytokine biologics, the response rate of rheumatoid arthritis treatment remains unsatisfactory, owing largely to the complexity of cytokine interactions and the multiplicity of cytokine targets. Here, we show a nanoparticle-based broad-spectrum anti-inflammatory strategy for rheumatoid arthritis management. By fusing neutrophil membrane onto polymeric cores, we prepare neutrophil membrane-coated nanoparticles that inherit the antigenic exterior and associated membrane functions of the source cells, which makes them ideal decoys of neutrophil-targeted biological molecules. It is shown that these nanoparticles can neutralize proinflammatory cytokines, suppress synovial inflammation, target deep into the cartilage matrix, and provide strong chondroprotection against joint damage. In a mouse model of collagen-induced arthritis and a human transgenic mouse model of arthritis, the neutrophil membrane-coated nanoparticles show significant therapeutic efficacy by ameliorating joint damage and suppressing overall arthritis severity.
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http://dx.doi.org/10.1038/s41565-018-0254-4DOI Listing
December 2018

The predictive value of high sensitivity-troponin velocity within the first 6h of presentation for cardiac outcomes regardless of acute coronary syndrome diagnosis.

Int J Cardiol 2016 Feb 23;204:106-11. Epub 2015 Nov 23.

School of Medicine, Flinders University of South Australia, Adelaide, Australia; Department of Cardiovascular Medicine, Southern Adelaide Local Health Network, Adelaide, Australia. Electronic address:

Background: Low-range troponin elevations without clear coronary manifestations remain a major diagnostic challenge. We sought to determine if troponin velocity could allow for early identification of patients without an obvious cardiac diagnosis and who are at increased risk for cardiac-specific events.

Methods & Results: All patients presenting to South Australian public hospitals between 1 September 2011 and 30 September 2012, with at least two troponin measurements during the first 6h after ED presentation were included. Diagnoses were classified as 'coronary', 'non-coronary cardiac', and 'non-cardiac' using the International Classification of Diseases 10 codes. The relationship between troponin velocity and cardiac-specific mortality and combined cardiac outcome (death and myocardial infarction) was assessed using Fine and Gray competing risk models in patients with an initial troponin <52 ng/L. Sensitivity analyses were performed using different initial and maximum troponin cut-off values. In total, 7300 patients were identified. A troponin velocity of 2.5 ng/L/h or greater in the non-cardiac (n=2793) patient group was significantly associated with an increased risk for 12-month cardiac mortality (sub-hazard ratio [SHR] 2.90, 95% CI 1.33-6.34) and combined cardiac outcome (SHR 2.08, 95% CI 1.01-4.27). This association was consistent for coronary (n=3835) and non-coronary cardiac (n=672) patient groups, and remained after sensitivity analyses.

Conclusions: The significant association observed across all patient groups suggests that troponin velocity could be used for early risk stratification of patients with low-range troponin elevations without clear cardiac symptoms. These results may help guide future clinical trials aimed at assessing the utility of cardiac-targeted interventions in this challenging patient population.
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http://dx.doi.org/10.1016/j.ijcard.2015.11.132DOI Listing
February 2016

High sensitivity-troponin elevation secondary to non-coronary diagnoses and death and recurrent myocardial infarction: An examination against criteria of causality.

Eur Heart J Acute Cardiovasc Care 2015 Oct 11;4(5):419-28. Epub 2014 Dec 11.

South Western Sydney Clinical School, University of New South Wales, Australia.

Background: Myonecrosis provoked by illness unrelated to unstable coronary plaque is common, but uncertainty about a cause-effect relationship with future events challenges the appropriateness of initiating therapies known to be effective in cardiac conditions. We examined the causal relationship between troponin elevation in non-coronary diagnoses and late cardiac events using the Bradford Hills criteria for causality.

Methods And Results: Patients presenting acutely to South Australian public hospitals receiving at least one troponin between September 2011-September 2012 were included. Diagnoses were classified as coronary, non-coronary cardiac and non-cardiac using the International Classification of Diseases, version 10 Australian Modified, codes. The relationship between peak in-hospital troponin, using a high-sensitivity troponin T assay and adjudicated cardiac and non-cardiac mortality, and subsequent myocardial infarction (MI) was assessed using competing-risk flexible parametric survival models. Troponin results were available for 38,161 patients of whom, 12,645 (33.6%), 3237 (8.5%), and 22,079 (57.9%) patients were discharged with coronary, non-coronary cardiac and non-cardiac diagnoses, respectively. Troponin >14 ng/l was observed in 43.6%. The relationship between troponin and cardiac mortality was stronger among the non-coronary diagnosis group (troponin 1000 ng/l: coronary hazard ratio: 5.1 (95% confidence interval (CI) 4.0-6.6) vs non-coronary hazard ratio: 16.3 (95% CI 12.6-22.4)). The temporal hazard for cardiac death was marked within 30 days in both groups. Among non-coronary diagnoses, the hazard for recurrent MI was higher but did not vary with time.

Conclusions: Consistency with causal criteria between secondary myonecrosis and cardiac events suggest the potential benefit for extending cardiac specific interventions to this population if supported in trials appropriately designed to address competing risks. Troponin elevation precipitated by non-coronary events is common and demonstrates an associations with late mortality that are analogous to spontaneous MI resulting from unstable coronary plaque. These observations help inform the design of randomized clinical trials exploring the benefits and risk of therapies with established benefits in other cardiac conditions. Such studies will need to appropriately account for competing risks in this population of patients.
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http://dx.doi.org/10.1177/2048872614564083DOI Listing
October 2015

Genetic deletion of Mst1 alters T cell function and protects against autoimmunity.

PLoS One 2014 22;9(5):e98151. Epub 2014 May 22.

Lexicon Pharmaceuticals, Inc, The Woodlands, Texas, United States of America.

Mammalian sterile 20-like kinase 1 (Mst1) is a MAPK kinase kinase kinase which is involved in a wide range of cellular responses, including apoptosis, lymphocyte adhesion and trafficking. The contribution of Mst1 to Ag-specific immune responses and autoimmunity has not been well defined. In this study, we provide evidence for the essential role of Mst1 in T cell differentiation and autoimmunity, using both genetic and pharmacologic approaches. Absence of Mst1 in mice reduced T cell proliferation and IL-2 production in vitro, blocked cell cycle progression, and elevated activation-induced cell death in Th1 cells. Mst1 deficiency led to a CD4+ T cell development path that was biased toward Th2 and immunoregulatory cytokine production with suppressed Th1 responses. In addition, Mst1-/- B cells showed decreased stimulation to B cell mitogens in vitro and deficient Ag-specific Ig production in vivo. Consistent with altered lymphocyte function, deletion of Mst1 reduced the severity of experimental autoimmune encephalomyelitis (EAE) and protected against collagen-induced arthritis development. Mst1-/- CD4+ T cells displayed an intrinsic defect in their ability to respond to encephalitogenic antigens and deletion of Mst1 in the CD4+ T cell compartment was sufficient to alleviate CNS inflammation during EAE. These findings have prompted the discovery of novel compounds that are potent inhibitors of Mst1 and exhibit desirable pharmacokinetic properties. In conclusion, this report implicates Mst1 as a critical regulator of adaptive immune responses, Th1/Th2-dependent cytokine production, and as a potential therapeutic target for immune disorders.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0098151PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4031148PMC
January 2015

Novel class of LIM-kinase 2 inhibitors for the treatment of ocular hypertension and associated glaucoma.

J Med Chem 2009 Nov;52(21):6515-8

Department of Medicinal Chemistry, Lexicon Pharmaceuticals, Princeton, New Jersey 08540, USA.

The discovery of a pyrrolopyrimidine class of LIM-kinase 2 (LIMK2) inhibitors is reported. These LIMK2 inhibitors show good potency in enzymatic and cellular assays and good selectivity against ROCK. After topical dosing to the eye in a steroid induced mouse model of ocular hypertension, the compounds reduce intraocular pressure to baseline levels. The compounds also increase outflow facility in a pig eye perfusion assay. These results suggest LIMK2 may be an effective target for treating ocular hypertension and associated glaucoma.
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http://dx.doi.org/10.1021/jm901226jDOI Listing
November 2009

Human and mouse trace amine-associated receptor 1 have distinct pharmacology towards endogenous monoamines and imidazoline receptor ligands.

Biochem J 2009 Oct 23;424(1):39-45. Epub 2009 Oct 23.

Department of Pharmaceutical Discovery, Lexicon Pharmaceuticals, Inc., 8800 Technology Forest Place, The Woodlands, TX 77381, USA.

TAARs (trace amine-associated receptors) are G-protein-coupled receptors that respond to low abundance, endogenous amines such as tyramine and tryptamine, and represent potential targets for neuropsychiatric diseases. However, some members of this receptor subfamily either have no ligand identified or remain difficult to express and characterize using recombinant systems. In the present paper we report the successful expression of human and mouse TAAR1, and the characterization of their responses to various natural and synthetic agonists. In HEK (human embryonic kidney)-293/CRE-bla cells, mouse TAAR1 showed a robust response to trace amines as measured using either a cAMP assay or a beta-lactamase reporter assay, whereas human TAAR1 showed a weaker, but still measurable, response. When certain fragments of human TAAR1 were replaced with the corresponding regions of mouse TAAR1, the chimaeric receptor showed a much stronger response in cAMP production. Examination of a series of agonists on these receptors revealed that the human and the chimaeric receptor are almost identical in pharmacology, but distinct from the mouse receptor. We also screened small libraries of pharmacologically active agents on TAAR1 and identified a series of synthetic agonists, some of which are also ligands of the enigmatic imidazoline receptor. The findings of the present study not only shed light on the pharmacological species difference of TAAR1, but also raise new possibilities about the mechanism of some of the imidazoline-related agents.
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http://dx.doi.org/10.1042/BJ20090998DOI Listing
October 2009

Factors Involved in Tactile Texture Perception through Probes.

Adv Robot 2009 ;23(6):747-766

Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA.

An understanding of texture perception by robotic systems can be developed by examining human texture perception through a probe. Like texture perception through direct touch with the finger, texture perception by indirect means of a probe is multi-dimensional, comprising rough, hard, and sticky texture continua. In this study, we describe the individual subject variability in probe-mediated texture perception, and compare similarities and differences of texture perception between direct touch and indirect touch. The results show variability among subjects, as individual subjects may choose to rely on different degrees of three texture dimensions and do so at different scanning velocities. Despite this variability between scanning conditions within each subject, the subjects make consistently reliable discriminations of textures and subjective magnitude estimates along texture continua when indirectly exploring texture surfaces with a probe. These data contribute information that is valuable to the design of robotic sensory systems, and to the understanding of sensory feedback, which is essential in teleoperations.
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http://dx.doi.org/10.1163/156855309X431703DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2711640PMC
January 2009
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