ap20187 and Inflammation

Fibulin-5, a multifunctional extracellular matrix protein, is up-regulated in response to mechanical injury and can promote dermal wound healing. This study aimed to explore the role and mechanism of Fibulin-5 in the pathogenesis of post-burn inflammation in thermally-injured mice. Here, we found that Fibulin-5 was up-regulated in the dorsal root ganglion (DRG) of burn-injured mice. After nociceptive behavioral testing, DRG was isolated and cultured to detect the mechanism of Fibulin-5 in thermal injury models by recombinant adenovirus overexpressing Fibulin-5, RT-qPCR, Western Blot, ELISA, AP20187 (an activator of one kind of kinase phosphorylating the α subunit of eukaryotic initiation factor 2, eIF2α), capsaicin (an agonist of transient receptor potential vanilloid (TRPV)-1), and an anti-CGRP neutralizing antibody. Also, the pathological state of skin tissues and the expression of cyclooxygenase 2 and myeloperoxidase were examined by Hematoxylin-Eosin staining and immunohistochemistry, respectively. We found that overexpression of Fibulin-5 attenuated the pain, inhibited the inflammatory response, and improved the pathologic condition induced by burn injury. Fibulin-5 overexpression significantly down-regulated the phosphorylation level of eIF2α and subsequently inhibited the TRPV1 channel and CREB/CGRP signaling. Additionally, anti-CGRP neutralizing antibody dramatically suppressed the inflammatory response induced by burn injury. The results suggest that overexpression of Fibulin-5 attenuates thermal inflammation via suppressing TRPV1/CGRP pathway. This may provide a potential therapy target to alleviate excessive inflammation in burn patients.

Topics: Animals; Burns; Extracellular Matrix Proteins; Ganglia, Spinal; Immunohistochemistry; Inflammation; Mice; Phosphorylation; Receptors, Calcitonin Gene-Related Peptide; Recombinant Proteins; Signal Transduction; Tacrolimus; TRPV Cation Channels; Up-Regulation

Macrophage (MΦ) dysregulation is increasingly becoming recognized as a risk factor for a number of inflammatory complications including atherosclerosis, cancer, and the host response elicited by biomedical devices. It is still unclear what roles the pro-inflammatory (M1) MΦ and pro-healing (M2) MΦ phenotypes play during the healing process. However, it has been shown that a local overabundance of M1 MΦs can potentially lead to a chronically inflamed state of the tissue; while a local over-exuberant M2 MΦ response can lead to tissue fibrosis and even promote tumorigenesis. These notions strengthen the argument that the tight temporal regulation of this phenotype balance is necessary to promote inflammatory resolution that leads to tissue homeostasis. In this study, we have engineered pro-inflammatory MΦs, MΦ-cTLR4 cells, which can be activated to a M1-like MΦ phenotype with a small molecule, the chemical inducer of dimerization (CID) drug. The MΦ-cTLR4 cells when activated with the CID drug, express increased levels of TNFα, IL-6, and iNOS. Activated MΦ-cTLR4 cells stay stimulated for at least 48h; once the CID drug is withdrawn, the MΦ-cTLR4 cells return to baseline state within 18h. Further, in vitro CID-activated MΦ-cTLR4 cells induce upregulation of VCAM-1 and ICAM-1 on endothelial cells (EC) in a TNFα-dependent manner. With the ability to specifically modulate the MФ-cTLR4 cells with the presence or absence of a small molecule, we now have the tool necessary to observe a primarily M1 MФ response during inflammation. By isolating this phase of the wound healing response, it may be possible to determine conditions for ideal healing.

Topics: Animals; Cell Engineering; Cells, Cultured; Inflammation; Macrophages; Mice; Neovascularization, Pathologic; Tacrolimus

Remyelination occurs in multiple sclerosis (MS) lesions but is generally considered to be insufficient. One of the major challenges in MS research is to understand the causes of remyelination failure and to identify therapeutic targets that promote remyelination. Activation of pancreatic endoplasmic reticulum kinase (PERK) signaling in response to endoplasmic reticulum stress modulates cell viability and function under stressful conditions. There is evidence that PERK is activated in remyelinating oligodendrocytes in demyelinated lesions in both MS and its animal model, experimental autoimmune encephalomyelitis (EAE). In this study, we sought to determine the role of PERK signaling in remyelinating oligodendrocytes in MS and EAE using transgenic mice that allow temporally controlled activation of PERK signaling specifically in oligodendrocytes. We demonstrated that persistent PERK activation was not deleterious to myelinating oligodendrocytes in young, developing mice or to remyelinating oligodendrocytes in cuprizone-induced demyelinated lesions. We found that enhancing PERK activation, specifically in (re)myelinating oligodendrocytes, protected the cells and myelin against the detrimental effects of interferon-γ, a key proinflammatory cytokine in MS and EAE. More important, we showed that enhancing PERK activation in remyelinating oligodendrocytes at the recovery stage of EAE promoted cell survival and remyelination in EAE demyelinated lesions. Thus, our data provide direct evidence that PERK activation cell-autonomously enhances the survival and preserves function of remyelinating oligodendrocytes in immune-mediated demyelinating diseases.

Topics: Animals; Axons; Cell Death; Cell Survival; Cuprizone; Cytoprotection; Demyelinating Diseases; eIF-2 Kinase; Encephalomyelitis, Autoimmune, Experimental; Enzyme Activation; Inflammation; Interferon-gamma; Mice; Mice, Inbred C57BL; Myelin Sheath; Oligodendroglia; Signal Transduction; Tacrolimus; Tremor

We describe the generation and characterization of the first inducible 'fatless' model system, the FAT-ATTAC mouse (fat apoptosis through targeted activation of caspase 8). This transgenic mouse develops identically to wild-type littermates. Apoptosis of adipocytes can be induced at any developmental stage by administration of a FK1012 analog leading to the dimerization of a membrane-bound, adipocyte-specific caspase 8-FKBP fusion protein. Within 2 weeks of dimerizer administration, FAT-ATTAC mice show near-knockout levels of circulating adipokines and markedly reduced levels of adipose tissue. FAT-ATTAC mice are glucose intolerant, have diminished basal and endotoxin-stimulated systemic inflammation, are less responsive to glucose-stimulated insulin secretion and show increased food intake independent of the effects of leptin. Most importantly, we show that functional adipocytes can be recovered upon cessation of treatment, allowing the study of adipogenesis in vivo, as well as a detailed examination of the importance of the adipocyte in the regulation of multiple physiological functions and pathological states.

Topics: Adipocytes; Adipose Tissue; Animals; Apoptosis; Caspase 8; Caspases; Dimerization; Eating; Enzyme Activation; Glucose Intolerance; Inflammation; Insulin; Insulin Secretion; Leptin; Lipodystrophy; Lipopolysaccharides; Mice; Mice, Transgenic; Recombinant Fusion Proteins; Tacrolimus; Tacrolimus Binding Proteins