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author:("Zhang, duchen")
1.  Proton pump inhibitor responsive esophageal eosinophilia, a distinct disease entity? 
World Journal of Gastroenterology : WJG  2014;20(30):10419-10424.
Recent studies have suggested the existence of a patient population with esophageal eosinophilia that responds to proton pump inhibitor therapy. These patients are being referred to as having proton pump inhibitor responsive esophageal eosinophilia (PPI-REE), which is currently classified as a distinct and separate disease entity from both gastroesophageal reflux disease (GERD) and eosinophilic esophagitis (EoE). The therapeutic effect of proton pump inhibitor (PPI) on PPI-REE is thought to act directly at the level of the esophageal mucosa with an anti-inflammatory capacity, and completely independent of gastric acid suppression. The purpose of this manuscript is to review the mechanistic data of the proposed immune modulation/anti-inflammatory role of the PPI at the esophageal mucosa, and the existence of PPI-REE as a distinct disease entity from GERD and EoE.
PMCID: PMC4130848  PMID: 25132757
Gastroesophageal reflux disease; Eosinophilic esophagitis; Proton pump inhibitor responsive esophageal eosinophilia; Proton pump inhibitor
2.  A Protective Hsp70-TLR4 Pathway in Lethal Oxidant Lung Injury 
Administering high levels of inspired oxygen, or hyperoxia, is commonly used as a life-sustaining measure in critically ill patients. However, prolonged exposures can exacerbate respiratory failure. Our previous study showed that toll-like receptor 4 (TLR4) confers protection against hyperoxia-induced lung injury and mortality. Hsp70 has potent cytoprotective properties and has been described as a TLR4 ligand in cell lines. We sought to elucidate the relationship between TLR4 and Hsp70 in hyperoxia-induced lung injury in vitro and in vivo and to define the signaling mechanisms involved. Wild type, TLR4−/− and Trif−/− (a TLR4 adapter protein) murine lung endothelial cells (MLEC) were exposed to hyperoxia. We found markedly elevated levels of intracellular and secreted Hsp70 from mice lung and MLEC after hyperoxia. We confirmed that Hsp70 and TLR4 co-immunoprecipitate in lung tissue and MLEC. Hsp70-mediated NFκB activation appears to depend upon TLR4. In the absence of TLR4, Hsp70 loses its protective effects in endothelial cells. Furthermore, these protective properties of Hsp70 are TLR4 adapter Trif-dependent, MyD88-independent. Hsp70-deficient mice have increased mortality during hyperoxia and lung-targeted adenoviral delivery of Hsp70 effectively rescues both Hsp70-deficient and wild type mice. Our studies are the first to define an Hsp70-TLR4-Trif cytoprotective axis in the lung and endothelial cells. This pathway is a potential therapeutic target against a range of oxidant-induced lung injuries.
PMCID: PMC3730854  PMID: 23817427
3.  Endothelial MKK3 is a critical mediator of lethal murine endotoxemia and acute lung injury 
Sepsis is a leading cause of intensive care unit admissions with high mortality and morbidity. Although outcomes have improved with better supportive care, specific therapies are limited. Endothelial activation and oxidant injury are key events in the pathogenesis of sepsis-induced lung injury. The signaling pathways leading to these events remain poorly defined and need to be studied. We sought to determine the role of MAP kinase kinase 3 (MKK3), a kinase of the p38 group in the pathogenesis of sepsis. We used a murine intraperitoneal lipopolysaccharide (LPS) model of systemic inflammation to mimic sepsis. Lung injury parameters were assessed in lung tissue and bronchoalveolar lavage. Primary lung endothelial cells were cultured and assessed for mediators of inflammation and injury such as ICAM-1, AP-1, NF-κB and mitochondrial ROS. Our studies demonstrate that MKK3 deficiency confers virtually complete protection against organ injury after intraperitoneal LPS. Specifically, MKK3 −/− mice were protected against acute lung injury, as assessed by reduced inflammation, mitochondrial reactive oxygen species (ROS) generation, endothelial injury and ICAM-1 expression after LPS. Our results show that endothelial MKK3 is required for inflammatory cell recruitment to the lungs, mitochondrial oxidant-mediated AP-1, NF-κB activation and ICAM-1 expression during LPS challenge. Collectively, these studies identify a novel role for MKK3 in lethal LPS responses and provide new therapeutic targets against sepsis and acute lung injury.
PMCID: PMC3552142  PMID: 23275604
4.  Era of universal testing of microsatellite instability in colorectal cancer 
Colorectal cancer (CRC) incidence and mortality are constantly decreasing, but CRC still remains the third most prevalent cancer and the third most common cause of cancer death in both males and females in the United States. Recent rapid declines in CRC incidence rates have largely been attributed to increases in screening that can detect and remove precancerous polyps, and the decrease in death rates for CRC largely reflects improvements in early detection, treatment and the understanding of molecular/genetic basis of CRC. One of the important molecular/genetic findings is the presence of microsatellite instability (MSI) in CRCs. Many studies have shown the importance of MSI testing in diagnosing Lynch syndrome and predicting prognosis and response to chemotherapeutic agents in CRCs. Increased emphasis has been placed on the importance of MSI testing for all newly diagnosed individuals with CRCs. Both immunohistochemical staining (IHC) and polymerase chain reaction (PCR)-based MSI testing show high sensitivity and specificity in detecting MSI. The current clinical guidelines and histopathology features are indicative of, but not reliable in diagnosing Lynch syndrome and CRCs with MSI. Currently, there are evidences that universal testing for MSI starting with either IHC or PCR-based MSI testing is cost effective, sensitive, specific and is getting widely accepted.
PMCID: PMC3613766  PMID: 23556052
Colorectal cancer; Lynch syndrome; Universal testing; DNA mismatch repair; Microsatellite instability
5.  Large ulcerated cecal lipoma mimicking malignancy 
Colonic lipomas are relatively uncommon tumors of mesenchymal origin, composed of well-differentiated adipose tissue supported by fibrous tissue, that usually occur in cecum and ascending colon. Colonic lipomas rarely cause symptoms and are usually detected incidentally. However, if the lesion is large, it may produce symptoms, such as abdominal pain, rectal bleeding, obstruction, intussusception, and even weight loss. Large colonic lipomas can be mistaken for malignancy, which may result in extensive surgical operations. We report a large broad-based ulcerated cecal lipoma in a 68-year-old woman, who presented with abdominal pain and weight loss. The ulcerated lesion was highly suspicious for malignancy radiologically and endoscopically. The patient underwent laparoscopic right-hemicolectomy, and the lesion was diagnosed as a cecal submucosal lipoma. The surgical approach remains the treatment of choice for large and complicated cases.
PMCID: PMC2999136  PMID: 21160661
Cecum; Lipoma; Carcinoma
6.  Toll-like receptor 4 deficiency causes pulmonary emphysema 
Journal of Clinical Investigation  2006;116(11):3050-3059.
TLRs have been studied extensively in the context of pathogen challenges, yet their role in the unchallenged lung is unknown. Given their direct interface with the external environment, TLRs in the lungs are prime candidates to respond to air constituents, namely particulates and oxygen. The mechanism whereby the lung maintains structural integrity in the face of constant ambient exposures is essential to our understanding of lung disease. Emphysema is characterized by gradual loss of lung elasticity and irreversible airspace enlargement, usually in the later decades of life and after years of insult, most commonly cigarette smoke. Here we show Tlr4–/– mice exhibited emphysema as they aged. Adoptive transfer experiments revealed that TLR4 expression in lung structural cells was required for maintaining normal lung architecture. TLR4 deficiency led to the upregulation of what we believe to be a novel NADPH oxidase (Nox), Nox3, in lungs and endothelial cells, resulting in increased oxidant generation and elastolytic activity. Treatment of Tlr4–/– mice or endothelial cells with chemical NADPH inhibitors or Nox3 siRNA reversed the observed phenotype. Our data identify a role for TLR4 in maintaining constitutive lung integrity by modulating oxidant generation and provide insights into the development of emphysema.
PMCID: PMC1616193  PMID: 17053835
7.  ERK1/2 mitogen-activated protein kinase selectively mediates IL-13–induced lung inflammation and remodeling in vivo 
Journal of Clinical Investigation  2005;116(1):163-173.
IL-13 dysregulation plays a critical role in the pathogenesis of a variety of inflammatory and remodeling diseases. In these settings, STAT6 is believed to be the canonical signaling molecule mediating the tissue effects of IL-13. Signaling cascades involving MAPKs have been linked to inflammation and remodeling. We hypothesized that MAPKs play critical roles in effector responses induced by IL-13 in the lung. We found that Tg IL-13 expression in the lung led to potent activation of ERK1/2 but not JNK1/2 or p38. ERK1/2 activation also occurred in mice with null mutations of STAT6. Systemic administration of the MAPK/ERK kinase 1 (MEK1) inhibitor PD98059 or use of Tg mice in which a dominant-negative MEK1 construct was expressed inhibited IL-13–induced inflammation and alveolar remodeling. There were associated decreases in IL-13–induced chemokines (MIP-1α/CCL-3, MIP-1β/CCL-4, MIP-2/CXCL-1, RANTES/CCL-5), MMP-2, -9, -12, and -14, and cathepsin B and increased levels of α1-antitrypsin. IL-13–induced tissue and molecular responses were noted that were equally and differentially dependent on ERK1/2 and STAT6 signaling. Thus, ERK1/2 is activated by IL-13 in the lung in a STAT6-independent manner where it contributes to IL-13–induced inflammation and remodeling and is required for optimal IL-13 stimulation of specific chemokines and proteases as well as the inhibition of specific antiproteases. ERK1/2 regulators may be useful in the treatment of IL-13–induced diseases and disorders.
PMCID: PMC1319220  PMID: 16374521

Results 1-7 (7)