Publications by authors named "Rishu Guo"

Background: Prior studies of peanut sublingual immunotherapy (SLIT) have suggested a potential advantage with younger age at treatment initiation.

Objective: We studied the safety and efficacy of SLIT for peanut allergy in 1- to 4-year-old children.

Methods: Peanut-allergic 1- to 4-year-old children were randomized to receive 4 mg peanut SLIT versus placebo.

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Background: Studies on the efficacy of peanut sublingual immunotherapy (SLIT) are limited. The durability of desensitization after SLIT has not been well described.

Objective: We sought to evaluate the efficacy and safety of 4-mg peanut SLIT and persistence of desensitization after SLIT discontinuation.

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Background: 10% of US residents have food allergies, including 2% with peanut allergy. Mast cell mediators released during the allergy effector phase drive allergic reactions. Therefore, targeting sensitized mast cells may prevent food allergy symptoms.

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Article Synopsis
  • The study investigated how quickly oral immunotherapy (OIT) affects mast cells and basophils in children receiving treatment for peanut allergies.
  • Results showed that after 9 months, many participants were desensitized, with early signs of basophil suppression observable by day 90, though individual responses varied.
  • Overall, the findings indicate that there is a significant suppression of basophil activation within 90 days of OIT which continues to develop over time, especially linked to changes in signaling molecules.
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Objectives: Dietary elimination for treatment of eosinophilic esophagitis (EoE) is limited by lack of accuracy in current allergy tests. We aimed to develop an immunologic approach to identify dietary triggers and prospectively test allergen-specific immune signature-guided dietary elimination therapy.

Methods: In the first phase, we developed and assessed 2 methods for determining selected food triggers using samples from 24 adults with EoE: a CD4+ T-cell proliferation assay in peripheral blood and food-specific tissue IgG4 levels in esophageal biopsies.

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Background: Peanut sublingual immunotherapy (SLIT) for 1 year has been shown to induce modest clinical desensitization in allergic children. Studies of oral immunotherapy, epicutaneous immunotherapy, and SLIT have suggested additional benefit with extended treatment.

Objective: We sought to investigate the safety, clinical effectiveness, and immunologic changes with long-term SLIT in children with peanut allergy.

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Background: Oral and sublingual immunotherapies for peanut allergy have demonstrated efficacy in small clinical trials; however, mechanisms and biomarkers correlating with clinical outcomes remain elusive. Previous studies have demonstrated a role for IgG in post-OIT plasma in the suppression of IgE-mediated mast cell reactions.

Objective: The aim of this study was to characterize the role that peanut oral and sublingual immunotherapy-induced plasma factors play in the inhibition of ex vivo basophil activation and whether inhibitory activity is associated with clinical outcomes.

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Article Synopsis
  • The study aimed to investigate food allergy traits using a genetically diverse group of mice to better understand genetic and environmental influences.
  • Researchers selected 16 strains of Collaborative Cross (CC) mice and tested their allergic reactions to peanuts, with a notable finding that only the CC027/GeniUnc strain suffered severe symptoms after oral peanut exposure.
  • The results highlighted the CC027/GeniUnc mice's genetic predisposition to peanut allergies, suggesting that these mice could be valuable models for future allergy research.
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Article Synopsis
  • The study investigates how oral immunotherapy (OIT) affects immune cells in preschoolers with peanut allergies, focusing on different maintenance doses (low vs. high).
  • It found that both low and high-dose OIT resulted in reduced levels of pro-allergic cytokines and decreased basophil activation, indicating improved tolerance to peanuts.
  • No significant differences were observed in immune responses between the low and high-dose groups, suggesting that lower doses may be as effective, which could influence treatment protocols for peanut allergies.
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Background: Oral immunotherapy (OIT) is an effective experimental food allergy treatment that is limited by treatment withdrawal and the frequent reversibility of desensitization if interrupted. Newly diagnosed preschool children may have clinical and immunological characteristics more amenable to treatment.

Objective: We sought to test the safety, effectiveness, and feasibility of early OIT (E-OIT) in the treatment of peanut allergy.

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Peanut allergy is an IgE-mediated hypersensitivity. Upon peanut consumption by an allergic individual, epitopes on peanut proteins bind and cross-link peanut-specific IgE on mast cell and basophil surfaces triggering the cells to release inflammatory mediators responsible for allergic reactions. Polyphenolic phytochemicals have high affinity to bind proteins and form soluble and insoluble complexes with unique functionality.

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Background: Peanut flour is a high-protein, low-oil, powdered material prepared from roasted peanut seed. In addition to being a well-established food ingredient, peanut flour is also the active ingredient in peanut oral immunotherapy trials. Enzymatic hydrolysis was evaluated as a processing strategy to generate hydrolysates from peanut flour with reduced allergenicity.

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Background: IgE-mediated allergic reactions to cashews and other nuts can trigger life-threatening anaphylaxis. Proactive therapies to decrease reaction severity do not exist.

Objectives: We aimed to determine the efficacy of pepsin-digested cashew proteins used as immunotherapy in a murine model of cashew allergy.

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Chemokines and chemokine receptors have been implicated in the pathogenesis of bronchiolitis. CXCR3 ligands (CXCL10, CXCL9, and CXCL11) were elevated in patients with bronchiolitis obliterans syndrome (BOS) and chronic allorejection. Studies also suggested that blockage of CXCR3 or its ligands changed the outcome of T-cell recruitment and airway obliteration.

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The molecular mechanisms of lung injury and fibrosis are incompletely understood. MicroRNAs (miRNAs) are crucial biological regulators that act by suppressing their target genes and are involved in a variety of pathophysiological processes. To gain insight into miRNAs in the regulation of lung fibrosis, total RNA was isolated from mouse lungs harvested at different days after bleomycin treatment, and miRNA array with 1,810 miRNA probes was performed thereafter.

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Pulmonary fibrosis is a progressive, dysregulated response to injury culminating in compromised lung function due to excess extracellular matrix production. The heparan sulfate proteoglycan syndecan-4 is important in mediating fibroblast-matrix interactions, but its role in pulmonary fibrosis has not been explored. To investigate this issue, we used intratracheal instillation of bleomycin as a model of acute lung injury and fibrosis.

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Both diacylglycerol (DAG) and phosphatidic acid (PA) are important second messengers involved in signal transduction from many immune cell receptors and can be generated and metabolized through multiple mechanisms. Recent studies indicate that diacylglycerol kinases (DGKs), the enzymes that catalyze phosphorylation of DAG to produce PA, play critical roles in regulating the functions of multiple immune cell lineages. In T cells, two DGK isoforms, alpha and zeta, inhibit DAG-mediated signaling following T-cell receptor engagement and prevent T-cell hyperactivation.

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Diacylglycerol (DAG) kinases (DGKs) are a family of enzymes that convert DAG to phosphatidic acid (PA), the physiologic functions of which have been poorly defined. We report here that DGK alpha and zeta synergistically promote T cell maturation in the thymus. Absence of both DGKalpha and zeta (DGKalpha(-/-)zeta(-/-)) results in a severe decrease in the number of CD4(+)CD8(-) and CD4(-)CD8(+) single-positive thymocytes correlating with increased DAG-mediated signaling.

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Mammalian Toll-like receptors (TLRs) recognize microbial pathogen-associated molecular patterns and are critical for innate immunity against microbial infection. Diacylglycerol (DAG) kinases (DGKs) regulate the intracellular levels of two important second messengers involved in signaling from many surface receptors by converting DAG to phosphatidic acid (PA). We demonstrate that the zeta isoform of the DGK family (DGKzeta) is expressed in macrophages (Mphi) and dendritic cells.

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Anergic T cells have altered diacylglycerol metabolism, but whether that altered metabolism has a causative function in the induction of T cell anergy is not apparent. To test the importance of diacylglycerol metabolism in T cell anergy, we manipulated diacylglycerol kinases (DGKs), which are enzymes that terminate diacylglycerol-dependent signaling. Overexpression of DGK-alpha resulted in a defect in T cell receptor signaling that is characteristic of anergy.

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The bioactive phospholipid lysophosphatidic acid (LPA) promotes cell proliferation, survival, and migration by acting on cognate G protein-coupled receptors named LPA(1), LPA(2), and LPA(3). We profiled gene expression of LPA receptors in androgen-dependent and androgen-insensitive prostate cancer cells and found that LPA(1) gene is differentially expressed in androgen-insensitive and LPA-responsive but not androgen-dependent and LPA-resistant cells. In human prostate specimens, expression of LPA(1) gene was significantly higher in the cancer compared with the benign tissues.

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Calcium and diacylglycerol are critical second messengers that together effect mast cell degranulation after allergen cross-linking of immunoglobulin (Ig)E-bound FcepsilonRI. Diacylglycerol kinase (DGK)zeta is a negative regulator of diacylglycerol-dependent signaling that acts by converting diacylglycerol to phosphatidic acid. We reported previously that DGKzeta-/- mice have enhanced in vivo T cell function.

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The androgen receptor (AR) is activated in prostate cancer patients undergoing androgen ablative therapy and mediates growth of androgen-insensitive prostate cancer cells, suggesting it is activated by nonandrogenic factors. We demonstrate that activated alpha subunit of heterotrimeric guanine nucleotide-binding G(s) protein activates the AR in prostate cancer cells and also synergizes with low concentration of androgen to more fully activate the AR. The G alpha(s) activates protein kinase A, which is required for the nuclear partition and activation of AR.

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Background: Dysregulated cell survival contributes to the poor efficacy of many chemotherapeutic regimens for patients with advanced prostate cancer. In this study we examined ability of the lipid growth factor lysophosphatidic acid (LPA), a G protein-coupled receptor (GPCR) ligand, to promote prostate cell survival.

Methods: PC3 cells were used as a model to study mechanisms involved in survival of androgen-insensitive prostate cancer cells.

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