Charlie Norwood VA Medical Center

About: Charlie Norwood VA Medical Center is a healthcare organization based out in Augusta, Georgia, United States. It is known for research contribution in the topics: Autophagy & Kidney. The organization has 349 authors who have published 490 publications receiving 16360 citations. The organization is also known as: Augusta VA Medical Center.

Investigating Individual Pre-trauma Susceptibility to a PTSD-Like Phenotype in Animals.

Abstract: Post-Traumatic Stress Disorder (PTSD) is a complex condition that develops after experiencing a severe emotional trauma, with or without physical trauma. There is no known cure and evidence-based treatments, which are effective in reducing symptoms, have low retention rates. It is therefore important, in addition to seeking new therapeutics, to identify ways to reduce the likelihood of developing PTSD. The fact that some, but not all, individuals exposed to the same traumatic event develop PTSD suggests that there is individual susceptibility. Investigating susceptibility and underlying factors will be better guided if there is a coherent framework for such investigations. In this review, we propose that susceptibility is a dynamic state that is comprised of susceptibility factors (before trauma) and sequalae factors (during or after trauma, but before PTSD diagnosis). We define key features of susceptibility and sequalae factors as: (1) they are detectable before trauma (susceptibility factors) or during/shortly after trauma (sequalae factors), (2) they can be manipulated, and (3) manipulation of these factors alters the likelihood of developing PTSD, thus affecting resilience. In this review we stress the importance of investigating susceptibility to PTSD with appropriate animal models, because prospective human studies are expensive and manipulation of susceptibility and sequalae factors for study purposes may not always be feasible. This review also provides a brief overview of a subset of animal models that study PTSD-related behaviors and related alterations in endocrine and brain systems that focus on individual differences, peri- and post-trauma. Attention is drawn to the RISP model (Revealing Individual Susceptibility to a PTSD-like Phenotype) which assesses susceptibility before trauma. Using the RISP model and expression of plasticity-associated immediate early genes, Arc and Homer1a, we have identified impaired hippocampal function as a potential susceptibility factor. We further discuss other putative susceptibility factors and approaches to mitigate them. We assert that this knowledge will guide successful strategies for interventions before, during or shortly after trauma that can decrease the probability of developing PTSD.

Inflammatory Pathways in Psychiatric Disorders: The case of Schizophrenia and Depression.

Abstract: A better understanding of the key molecules/pathways underlying the pathophysiology of depression and schizophrenia may contribute to novel therapeutic strategies. In this review, we have discussed the recent developments on the role of inflammatory pathways in the pathogenesis of depression and schizophrenia. Inflammation is an innate immune response that can be triggered by various factors, including pathogens, stress, and injury. Under normal conditions, the inflammatory responses quiet after pathogen clearance and tissue repair. However, abnormal long-term or chronic inflammation can lead to damaging effects. Accumulating evidence suggest that dysregulated inflammation is linked to the pathogenesis of neuropsychiatric disorders. In this review, we have discussed the roles of complement system, infiltration of peripheral immune cells into the central nervous system (CNS), the gut-brain axis, and the kynurenine pathway in depression and schizophrenia. There is a large body of compelling evidence on the role of inflammatory pathways in depression and schizophrenia. Although most of these findings show their roles in the pathophysiology of the above disorders, additional studies are warranted to investigate the therapeutic potential of various immune signaling targets discussed in this article.

Anti-Psoriatic Drug Monomethylfumarate Increases Nuclear Factor Erythroid 2-Related Factor 2 Levels and Induces Aquaporin-3 mRNA and Protein Expression.

Abstract: Oxidative stress contributes to inflammatory skin diseases, including psoriasis. Monomethylfumarate (MMF) is an antipsoriatic agent with a poorly understood mechanism of action. In other cell types MMF increases the expression of nuclear factor erythroid-derived 2-like 2 (Nrf2), a transcription factor that regulates cellular antioxidant responses, to reduce oxidative stress like that observed in inflammatory disorders such as multiple sclerosis. We tested the hypothesis that MMF enhances Nrf2 activity in keratinocytes, thereby improving their capacity to counteract environmental stresses. We used Western analysis, immunofluorescence, and real-time quantitative reverse-transcription polymerase chain reaction to examine the effect of MMF on the expression of Nrf2 and its targets. We also measured intracellular reactive oxygen species (ROS) levels following MMF treatment. Our data show that MMF increased total and nuclear Nrf2 levels in primary mouse keratinocytes and enhanced mRNA expression of several Nrf2-downstream effectors, including heme oxygenase-1 and peroxiredoxin-6. Moreover, MMF treatment attenuated the generation of ROS following hydrogen peroxide treatment. On the other hand, the expression and membranous localization of aquaporin-3 (AQP3), a glycerol channel implicated in keratinocyte differentiation, was stimulated by MMF, which also enhanced keratinocyte glycerol uptake. The Nrf2 activator sulforaphane also increased AQP3 levels, suggesting that AQP3 expression may be regulated by Nrf2. We show for the first time that MMF stimulates Nrf2 and AQP3 expression and function/activity in keratinocytes. This effect may account, in part, for the previously observed ability of MMF to inhibit proliferation and inflammatory mediator production and promote differentiation in keratinocytes and to treat psoriasis.

Differential regulation of myosin X movements by its cargos, DCC and neogenin

Abstract: Myosin X (Myo X), also known as MYO10, is an unconventional actin-based motor protein that plays an important role in filopodium formation. Its intra-filopodia movement, an event tightly associated with the function of Myo X, has been extensively studied. However, how the motor activity of Myo X and the direction of its movements are regulated remains largely unknown. In our previous study, we demonstrated that DCC (for 'deleted in colorectal carcinoma') and neogenin (neogenin 1, NEO1 or NGN), a family of immunoglobin-domain-containing transmembrane receptors for netrins, interact with Myo X and that DCC is a cargo of Myo X to be delivered to the neurites of cultured neurons. Here, we provide evidence for DCC and neogenin as regulators of Myo X. DCC promotes movement of Myo X along basal actin filaments and enhances Myo-X-mediated basal filopodium elongation. By contrast, neogenin appears to suppress Myo X movement on the basal side, but increases its movement towards the apical and dorsal side of a cell, promoting dorsal filopodium formation and growth. Further studies have demonstrated that DCC, but not neogenin, enhances integrin-mediated tyrosine phosphorylation of focal adhesion kinase and basal F-actin reorganization, providing a cellular mechanism underlying their distinct effects on Myo X. These results thus demonstrate differential regulatory roles on Myo X activity by its cargo proteins, DCC and neogenin, revealing different cellular functions of DCC and neogenin.